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311637, CANRIMT, NSERC, Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada; PSI2013-40768-P, MINECO, Ministerio de Economía y Competitividad, Grant SI2013-40768-P from the Ministerio de Economıa y Competitividad (Spain)

The use of anesthetics in Angelfish ( Pterophyllum scalare ) has not been fully explored. The aim of this study is to determine the lowest effective dose (LED) of three anesthetics (2-phenoxyethanol, clove oil and tricaine methanesulphonate (MS-222)) and their effect after multiple exposures at 24 and 48 h. Each agent was tested on ten juvenile angelfish at four different doses. Considering the effect criteria of complete anesthetic induction time within 3 min and recovery time within 5 min, LEDs were established at 800 mg L − 1 for 2-phenoxyethanol, 100 mg L − 1 for clove oil and 140 mg L − 1 for MS-222. Different anesthesia and recovery times should be considered when repeated exposures during consecutive days are performed on juvenile angelfish.

The aim of this study was to evaluate the effect of hydrogen peroxide, iodine solution (PVP) and methylene blue on eggs disinfection of three ornamental fish species, Danio rerio, Pterophyllum scalare and Gymnocorymbus ternetzi. The main idea was to create conditions to enhance the hatching rates. Eggs of each species were exposed to different concentrations of hydrogen peroxide (5, 10, 15 and 25 mg/L), PVP (0.25, 0.5, 0.75 and 1 mg/L) and methylene blue (0.5 1, 2 and 3 mg/L). The optimal doses ranged between species and chemicals: for G. ternetzi, the concentrations that high enhanced the hatching rate were 1 mg/L for the PVP treatment, 25 mg/L for the hydrogen peroxide treatment and 3 mg/L for methylene blue treatment; for P. scalare, the best results were achieved with 25 mg/L for hydrogen peroxide treatment and 3 mg/L for methylene blue treatment. By contrast, for all the different chemical did not increased the D. rerio hatching rate. Results showed that hydrogen peroxide and methylene blue are the most versatile, effective and safe to use in these species. On the other hand, PVP can be used but with many precautions due to very low safety margin. Results clearly show that the optimal concentration of chemicals for eggs disinfection is fish species dependent and it is completely wrong to extrapolate concentrations between different chemicals and fish species. Our study suggests that P. scalare can be used as a model in study of effectiveness of new chemicals with potential to disinfect water and increase hatching rates.

Tetrahymena is a ciliated protozoan that can infect a wide range of fish species, although it is most commonly reported in guppies (Poecilia reticulata). The aim of this study was to compare the susceptibility to infection with Tetrahymena of five different ornamental fish species from two different super orders. The species examined were platy (Xiphophorus), molly (Poecilia sphenops) and angelfish (Pterophyllum scalare) of the Acanthopterygii super order (which also includes guppies) and goldfish (Carassius auratus auratus) and koi carp (Cyprinus carpio) of the Ostariophysi super order. These two super orders are phylogenetically distant from each other. Infection with Tetrahymena resulted in parasite invasion of internal organs, skin and muscle in all fish species. A relatively strong inflammatory response was observed in infected goldfish and koi, with negligible response in fish species of the Acanthopterygii super order. Guppies were the most susceptible to Tetrahymena infection, exhibiting a mortality rate of 87% and 100% in two separate experiments. A high mortality rate was also observed in platy (77%), while that of molly and angelfish was significantly lower (23% and 33%, respectively). Goldfish and koi carp were less susceptible to infection compared with guppies (24% and 59% mortality, respectively). Immunization studies revealed that the Tetrahymena are immunogenic, since infection of koi carp increased their Tetrahymena immobilization response by approximately three-fold at 3 weeks post infection, while immunization with Tetrahymena plus adjuvant increased their immobilization response by approximately 30-fold.

This study aimed to evaluate the effectiveness of eugenol for the induction and anaesthesia recovery of freshwater angelfish juveniles, and to verify its effectiveness for transportation. Juveniles were exposed to different concentrations of eugenol: 0 (control), 10, 15, 20, 30, 40, 50 and 60 μL L−1 (equivalent to 10.6, 15.9, 21.2, 31.8, 42.4, 53.0 or 63.6 mg L−1). Afterwards, other fish were divided into two groups: sedated with 15.9 mg L−1 eugenol and non-sedated, and they were evaluated 4 and 7 h after transportation. The minimum effective concentration for sedation and anaesthesia occurred with 15.9 and 53.0 mg L−1 eugenol, respectively. The total ammonia was significantly higher in the control group than the sedated group 7 h after transportation. Blood glucose levels were significantly higher in the sedated fish in relation to the control group 7 h after transportation. The gill histopathology analysis and muscle glycogen levels were not influenced by eugenol or the time of transportation. It is concluded that 15.9 and 53.0 mg L−1 eugenol were effective concentrations for sedation and anaesthesia in juveniles, and that 15.9 mg L−1 eugenol has the potential to be used for the transportation of freshwater angelfish for up to 7 h.

The present study aimed to evaluate the effect of salinity and feeding frequency on zootechnical performance of Pterophyllum scalare and Heros severus five-day-old post-larvae. Two experiments were performed in a completely randomized experimental design in a 5 × 2 factorial scheme, with 5 different NaCl concentrations (0, 2, 4, 6 and 8 g/L) and 2 feeding frequencies (2 and 4 times a day). P. scalare showed the highest survival rates (p

Current study evaluates the macrophyte biomass of water hyacinth, Eichhornia crassipes, in diet food to improve the growth and survival of angelfish, Pterophyllum scalare . The liquid (extract) and ground modes are employed. Specific growth rate, weight gain, feed intake and final body weight in basal diet and macrophyte extract biomass diets were similar (p > 0.05). Fish survival was high in all dietary treatments (> 90%), while survival percentage of 100% was reported in ground macrophyte biomass treatment. Ground macrophyte biomass may be included in the diet of P. scalare up to 5%. The inclusion of E. crassipes in the diet of P. scalare proved similar or better results than basal diet. The macrophyte proved to be a food strategy in angelfish diets that may be implemented in the species’s diet at 32% levels of crude protein. The latter, easily found in tropical regions, affects directly the species’s growth and survival rates.

Spironucleus vortens is a protozoan fish parasite of veterinary and economic importance in the ornamental aquaculture industry. Despite this, key aspects of the life cycle of this organism, including its mode of transmission, have not been fully elucidated. We developed a non-invasive method for quantifying S. vortens in freshwater angelfish, which was then used to investigate parasite transmission and aggregation within host populations. As previously observed for S. meleagridis and S. salmonis, motile S. vortens trophozoites were detected in host faeces using light microscopy. Species-level identification of these flagellates was confirmed using 16S rDNA PCR. Faecal trophozoite counts were significantly correlated with trophozoite counts from the posterior intestine, the primary habitat of the parasite. This novel finding allowed effective prediction of intestinal parasite load from faecal counts. Overall, faecal count data revealed that 20% of hosts harbour 83% of parasites, conforming to the Pareto Principle (80/20 rule) of parasite aggregation with implications for parasite transmission. Trophozoites survived for ≥36 d outside the host within faeces and remained motile at low pH (comparable with that of angelfish stomach). No putative S. vortens cysts were observed in cultures or faecal samples. This calls into question the commonly accepted hypothesis that a protective cyst is required in the life cycle of S. vortens to facilitate transmission to a new host.

Anesthetics play an important role in fisheries research and aquaculture and are used to facilitate various handling procedures, such as weighing, sorting, collection of eggs and milt, tagging and medical treatment. Clove oil and benzocaine are approved anesthetic by US Food and Drug Administration. The present study investigates the effect of anesthetics on the respiratory metabolic parameters such as O 2 consumption rate, CO 2 output rate, NH 3 -N excretion rate, RQ, AQ and opercular activity of Angel fish, Pterophyllum scalare . The concentration of clove oil and benzocaine were selected based on the time of induction of sedation and recovery of the Angel fish. The concentration of clove oil selected for the Angel fish were 5 ppm, 15 ppm, 30 ppm, 45 ppm, 55 ppm and the benzocaine concentration were 30 ppm, 45 ppm, 50 ppm, 100 ppm, 200 ppm, 300 ppm and 400 ppm. The minimum values of respiratory metabolic parameters in clove oil-anaesthetized Angel fish P.scalare were observed at the concentration of 45 ppm while the same was in 50 ppm in the case of benzocaine treatment. Simulated transportation experiments were conducted for Angel fish and the results suggested that 50ppm benzocaine was the optimum dose of anaesthetics for safe transport of Angel fish.

Mass mortalities of angelfish eggs accompanied with very low hatchability were reported in a private ornamental fish farm in Egypt. Examined eggs were badly damaged by water mould that was decisively confirmed as Saprolegnia species. Presumptive identification of the ten retrieved isolates was initially suggestive of Saprolegnia species. Mycological investigations have revealed that only 7 out of 10 isolates were capable of producing sexual stages. Therefore, using molecular tools such as PCR coupled with partial sequencing of inter-transcribed spacer (ITS) gene was one of the most important approaches to distinguish Saprolegnia parasitica from other water moulds. The sequences of ITS gene data derived from eight isolates showed 100% similarity with S. parasitica ATCC90312 sequence and the remaining two isolates were different in one nucleotide (99.9%). The phylogenetic analysis of ITS genes grouped the ten isolates with other S. parasitica in one clad. Further, to control such fungal infection, the efficacy of povidone iodine as surface disinfectant for angelfish and their fertilized eggs were tested. By trial, it was obvious that the obtained post-rinsing results were highly suggestive for the efficacy of povidone iodine as an efficient antifungal disinfectant for both fish and eggs.

CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico Com o estudo objetivou-se avaliar o efeito da salinidade e da frequência de alimentação no crescimento, uniformidade e sobrevivência de pós-larvas de acará bandeira Pterophyllum scalare e acará severo Heros severus. Foram realizados dois experimentos em delineamento experimental inteiramente casualizado em esquema fatorial 5 x 2, com cinco diferentes concentrações de cloreto de sódio (0; 2; 4; 6 e 8 g L-1), duas frequências alimentares (2 e 4 vezes ao dia) e quatro repetições. Foi observado que a salinidade da água e a frequência alimentar influenciaram significativamente (p < 0,05) no comprimento do tronco e altura do corpo de larvas de acará bandeira. O diâmetro do olho foi influenciado (p < 0,05) apenas pela salinidade, enquanto que o comprimento padrão final, ganho de comprimento padrão, comprimento da cabeça, comprimento do tronco, comprimento pós-anal, altura da cabeça, altura do corpo, peso final, ganho de peso, taxa de crescimento específico e fator de condição alométrico diferiram significativamente (p < 0,05) pela frequência de alimentação. Na larvicultura do acará severo, houve diferença significativa (p < 0,05) no comprimento da cabeça, comprimento pós-anal, altura da cabeça e fator de condição alométrico pela salinidade e frequência alimentar. A salinidade da água influenciou significativamente (p < 0,05) o comprimento padrão final, ganho de comprimento padrão, comprimento do tronco, diâmetro do olho, altura do corpo, taxa de sobrevivência e uniformidade em peso. A frequência alimentar influenciou significativamente (p < 0,05) o peso final, ganho de peso e taxa de crescimento específico. Concluiu-se que as pós-larvas de acará bandeira podem ser cultivadas com salinidade de até 4 g L-1 sem problemas ao desenvolvimento e sobrevivência. Por outro lado, as pós-larvas de acará severo obtiveram melhor taxa de sobrevivência em água sem adição de sal. A frequência alimentar de quatro vezes ao dia com náuplios de Artemia é a mais recomendada para ambas as espécies. With the study aimed to evaluate the effect of salinity and feeding frequency on growth, uniformity and survival of the angelfish Pterophyllum scalare and banded cichlid post-larvae. Were conducted two experiments in a completely randomized in a factorial 5 x 2, with five different sodium chloride concentrations (0; 2; 4; 6 and 8 g L-1) and two feed frequency (2 and 4 times per day). It was observed the water salinity and feeding frequency influenced significantly (p < 0,05) in torso length and body height in the angelfish larviculture. The eye diameter, was affected (p < 0,05) only by salinity, while the final standard length, standard length gain, head length, torso length, post-anal length, head height, body height, final weight, weight gain, specific growth rate and allometric condition factor differed significantly (p < 0,05) only for the feeding frequency. In the banded cichlid larviculture, there was a significant difference (p < 0,05) in the head length, post-anal length, head height and allometric condition factor by salinity and feeding frequency. The water salinity influenced significantly (p < 0,05) the final standard length, standard length gain, torso length, eye diameter, body height, survival hate and uniformity in weight. The feeding frequency influenced significantly (p < 0,05) the final weight, weight gain and specific growth rate. It was concluded that angelfish post-larvae can be grown with salinity up to 4 g L-1 without problems for the development and survival. On the other hand, the banded cichlid post-larvae had better survival hate in water without salt add. The feeding frequency of four times a day with artemia nauplii is the most recommended for the both species.

Angelfish (Pterophyllum scalare) is a very important species in Brazil's domestic market, however feeding managements differ from fish breeders to aquarists, so the cost of feed and labor become relevant items when cultivating the species. The objective of this research was to assess feeding frequency and feed deprivation based on growth performance, parasite infestation and cost-benefit in farming this species. The experiment was conducted in a completely randomized design in a 3x2 factorial scheme with 3 daily feeding levels, 4 meals, 2 meals and 1 meal; with and without feed deprivation and two repetitions. Feed deprivation consisted of offering feed 5 days a week only. Feeding twice a day without deprivation and four times a day with or without feed deprivation resulted in higher growth performance than feeding once a day. Monogenean and nematode parasitic loads were not influenced by feeding management. The cost-benefit analysis enabled us to observe that the treatment with the best benefit was the one involving two feedings a day with no deprivation. Thus, considering the parameters mentioned above, we concluded that the two daily feedings with no feed deprivation is the most adequate for farming this specie. RESUMO: O acará bandeira (Pterophyllum scalare) é uma espécie muito importante no mercado interno do Brasil, no entanto o manejo alimentar difere entre os criadores de peixes para os aquaristas, levando em consideração o custo da alimentação e mão de obra. O objetivo deste trabalho foi avaliar o efeito da frequência de alimentação no desempenho na infestação do parasita e custo-benefício em acará bandeira de cultivo. O ensaio foi conduzido em um delineamento inteiramente casualizado em um esquema fatorial 3x2, sendo níveis de alimentação diários (4, 2 e 1 refeições) e 2 manejos (com e sem privação de alimentação), cada tratamento com duas repetições. Alimentação duas vezes por dia sem privação e quatro vezes por dia, com ou sem alimentação resultou no desempenho de crescimento, cargas parasitárias de monogeneas e nematoides não foram influenciados pelo manejo alimentar. A análise de custo-benefício nos permitiu observar que o tratamento envolvendo duas refeições por dia com nenhuma privação foi melhor. Conclui-se que o tratamento com duas refeições diárias sem privação alimentar é a mais adequada para o cultivo dessa espécie.

A feeding trail was conducted on juvenile of angel fish Pterophyllum scalare to investigate the effect of three different diets such as animal based protein, plant based protein and mixed protein on growth and survival rate of the fish. Juvenile Pterophyllum scalare were divided into three groups, fed with three different protein based diets along with control group. Before the feeding trail, the initial length and weight were measured. During the 4 weeks of experiment, fish were fed 3% body weight at a daily rate. The findings of the present study indicated that the growth and survival rate of angel fish Pterophyllum scalare varied significantly (P

The aim of this study was to investigate monogenean fauna in gills of Geophagus camopiensis, Pterophyllum scalare, Satanoperca jurupari, and Satanoperca acuticeps in a tributary from the Amazon River system in Brazil. A total of 2,148 monogenean specimens were collected from 140 fish examined from March 2012 to March 2013, and 84.3% of these fish were parasitized by 1 or more species. Such monogeneans were: Sciadicleithrum geophagi, Sciadicleithrum juruparii, Gussevia spiralocirra and Gyrodactylus sp. However, only G. camopiensis was parasitized by more than 1 species of monogenean, while S. jurupari and S. acuticeps were parasitized by the same species. Prevalence, mean intensity and mean abundance varied among host species and the highest levels of infection were by G. spiralocirra followed by S. geophagi, both parasites with aggregated dispersion. Abundance of monogeneans was not influenced by the size of the host. In G. camopiensis, the infection levels by S. geophagi did not vary during the rainy or drainage seasons. This is the first study on monogenean infections for G. camopiensis and S. acuticeps.

Three different live diets, Eucyclops serrulatus, Ceriodaphnia quadrangula and equal combination of E. serrulatus copepodid and C. quadrangula, were offered to angelfish (Pterophyllum scalare) larvae viz 1-week, 2-week and 3-week old at prey densities of 2, 5 and 10 individuals mL−1. Results showed that 1-week-old P. scalare larvae consumed E. serrulatus copepodid at a rate of 31.3–56.7 ind. h−1, C. quadrangula at 8.0–12.0 ind. h−1, and mixture of E. serrulatus and C. quadrangula at 20.7–40.7 ind. h−1. For 2-week- and 3-week-old larvae, consumption rate increased accordingly. The electivity indices (E) of P. scalare (1-week-old larvae) for E. serrulatus copepodid were +0.18, +0.23 and +0.22 at prey densities of 2, 5 and 10 ind. mL−1 respectively. Tendency towards E. serrulatus copepodid consumption reduced by aging P. scalare as indicated by the E values for 2- and 3-week-old larvae. However, growth and survival of P. scalare larvae was greatest when fed on combination of copepod E. serrulatus and C. quadrangula.

Summary A study was conducted to determine the effects of increasing the levels of dietary carotenoid-rich microalgae biomass on the skin colouration of angelfish (Pterophyllum scalare). A natural microalgae product characterised by a high content (approximately 5% w/w) of the carotenoid astaxanthin was included in a basal diet at 0.25, 0.50, 1.00 and 2.00 g per 100 g as a substitute for wheat flour. Each diet was fed at 3% of live weight to three replicates of 10 fish each for a period of 28 days. Final weights of replicates were determined as indications of growth. Further, non-invasive techniques were applied to evaluate skin colour. Whole body images of individual fish were processed using specialised computer software to measure the different components of the RGB, HSV and CIE L*a*b* colour evaluation systems, which were also assessed by three independent judges familiar with the rearing and trade of ornamental fishes. No significant influence of the microalgae addition was detected (P > 0.05) on the final live weight of the fish. The colour components Red, Hue, Value and L* were not linearly related (P

In this study, we evaluated the production potential of the polyculture of Freshwater Angelfish (Pterophyllum scalare, Cichlidae) and Pacific white shrimp (Litopenaeus vannamei). Two experimental trials were set up. The first trial entailed the use of a randomized design to investigate three treatments options: angelfish monoculture, shrimp monoculture, and fish and shrimp polyculture in 12 experimental 15 m2 ponds. In the second trial, we investigated two treatments (polyculture of caged fish and uncaged fish) in 10 experimental units. In trial 1, polyculture negatively affected fish growth and survival. However, fish did not affect shrimp growth and the greatest profit was achieved in polyculture. In trial 2, caging fish improve the growth of both fish and shrimp. An economic analysis showed the greatest profit and benefit cost ratio for caged fish compared with uncaged fish. We conclude that growing P. scalare and L. vannamei together is a better strategy than shrimp monoculture in low-salinity water. The use of caged fish in such a polyculture operation would enhance productivity and profitability.

Prey survivorship can vary with average space size/prey width (Sp/Py) and total cover within an area (Ct/At). Hypotheses predict that prey survivorship is maximized at intermediate Sp/Py values and that prey survivorship increases rapidly from zero to low cover but increases at a slower rate as cover increases further. Freshwater angelfish Pterophyllum scalare made choices between artificial vegetation treatments consistent with these predictions. At constant low cover, fish did not exhibit any space width preferences. At constant medium cover, fish significantly preferred a narrower space treatment over a wider space treatment. At constant high cover, fish significantly preferred a wider space treatment over narrower space treatments. At constant Sp/Py, fish exhibited a marked preference for a higher-cover treatment at low-cover levels. They also preferred higher cover treatments under higher cover levels, but these preferences were not as pronounced. Sp/Py and Ct/At both influenced the fishes’ habitat c...

This study investigated the effects of dietary salt (NaCl) levels on growth performance and salinity tolerance of angel fish (Pterophyllum scalare). Five diets were supplemented with 0 (control), 7.5, 15, 22.5, and 30 g kg−1 salt, respectively. Over 56 days, weight gain and specific growth rate were similar for the fish fed diets supplemented with 0 (control), 22.5, and 30 g kg−1 salt (P > 0.05), but slightly lower than fish fed the 7.5 and 15 g kg−1 salt diets. Results showed that addition of 7.5 and 15 g kg−1 salt to diets slightly increased specific growth rate (SGR), while decreased food coefficient ratio (FCR) and the highest final weight were observed in fish fed the diet containing 7.5 g kg−1 salt. There was no significant difference in survival rate among groups at experimental period (P > 0.05). At the end of experiment, the angel fish were exposed to salinity stress (6, 9, and 12 ppt). There was no significant obvious trend in survival index after 48-h salinity stress (P < 0.05).

The influence of fatty acid composition of the diets on the productive performance and on cold and heat tolerance of juvenile freshwater angelfish (Pterophyllum scalare), in three different phases, was studied. Phase I studied the productive performance of freshwater angelfish in a completely randomized experimental design with four treatments, canola, linseed, olive and soybean oils and four replicates during 50 days using 192 fish in 16 aquaria. Phase II studied the cold tolerance of juvenile freshwater angelfish using 72 juvenile freshwater angelfish, coming from phase I and maintained in 12 aquaria climatized chamber. The temperature was reduced 1ºC per day, until the observation of 100% fish mortality. Phase III, it was studied the heat tolerance of juvenile freshwater angelfish employing an identical procedure to phase II, but with a daily increase of 1ºC. Significant differences (P>0.05) were not observed for any parameters evaluated. Thus, it was concluded that the type of vegetable oil (canola, linseed, olive and soybean) used as a diet supplement did not affect the productive performance, nor the tolerance to cold and heat, of juvenile freshwater angelfish. Avaliou-se a influência da suplementação de lipídeos na dieta, com diferentes composições de ácidos graxos, sobre o desempenho produtivo e tolerância ao frio e ao calor de juvenis de acará-bandeira (Pterophyllum scalare). O experimento foi realizado em três fases. Na fase um avaliou-se o desempenho produtivo dos peixes em delineamento inteiramente ao acaso com quatro tratamentos - óleos de canola, linhaça, oliva e soja - e quatro repetições, durante 50 dias usando 192 peixes distribuídos em 16 aquários. Na segunda fase, avaliou-se a tolerância ao frio, usando 72 peixes, procedentes da fase um, distribuídos em 12 aquários e mantidos em câmara climatizada. A temperatura foi reduzida de 1ºC por dia até a observação de 100% de mortalidade dos peixes. Na fase três, avaliou-se a tolerância ao calor com procedimentos semelhantes aos da fase dois, porém a temperatura foi elevada 1ºC por dia. Não foram observadas diferenças significativas (P>0,05) para os parâmetros avaliados. Conclui-se que a suplementação de óleos vegetais nas dietas não inferiu no desempenho produtivo e na tolerância ao frio e ao calor de juvenis de acará-bandeira.

Somite differentiation, muscle fibres formation and growth were analysed in a non-model tropical fish Pterophyllum scalare. In this study, it was found that during somite differentiation, a primary myotome appears. The primary myotome is filled with multinucleated myotubes that constitute the major part of the somite. Subsequently, Pax-3 (paired-box protein)-positive cells, located externally to the myotomes, appear. In post-hatching stages, mononucleated proliferating cell nuclear antigen-positive cells are observed in the inter-myotomal spaces and within the myotomes. The mononucleated cells, situated in the myotomes, first express desmin in their cytoplasm and then Pax-7 (paired-box protein) in their nuclei. Expression of desmin indicates that they will enter myogenic pathway, whereas expression of Pax-7 suggests their role of satellite cells. We assume that mononucleated intramyotomal cells are myogenic precursors involved in muscle growth. In advanced (post-hatching) stages of myogenesis, myotomes contain both primary and new muscle fibres. Morphometric analyses show that in Pterophyllum scalare, growth of muscle fibres is mainly a result of hypertrophy.

Summary Environments and experiences encountered in early life stages of animals shape their adult behaviour. When environments are maintained for several generations, differential selection forces act upon individuals to select those most fit to the particular conditions. As such, differences in the behaviour of captive bred and wild caught individuals have been observed recurrently. In fish, hatchery raised individuals tend to seek refuge less, making them more vulnerable to predators. We tested the hypothesis that captive breeding induces non-adaptive changes in behaviour of freshwater angelfish, Pterophyllum scalare. Wild-caught and captive-bred fish were exposed to a natural predator and measured for their anti-predator behaviours; no differences were found in behaviour under control conditions. When exposed to a natural predator, wild-caught fish exhibited significantly shorter freezing durations than captive-bred fish, and took significantly shorter time to resume normal behaviour. No differences in the time taken to initiate investigations of the predator were detected. The results demonstrate that captive-bred fish respond differently than their wild counterparts when exposed to a natural predator, and that this domestication has implications for captive rearing programmes.

The ability to discriminate between larger and smaller quantities has been demonstrated in several mammalian and avian species suggesting the possibility of evolutionary conservation of this characteristic. Preference for the larger of two groups has also been shown in fish species, although this ability has rarely been systematically studied in lower order vertebrates, and thus the mechanisms of such ability are not understood. Here, we exploit the tendency of angelfish to seek protection in an unfamiliar environment by joining a group of conspecifics, a behaviour called shoaling. Test fish were given a simultaneous choice between shoals varying both in terms of numerical ratios and absolute numbers of fish. Our results provide evidence for quantity discrimination in angelfish. In general, experimental subjects chose the larger of two shoals. Furthermore, in agreement with Weber's law, which holds that discrimination between two quantities depends on their ratio, the discrimination between shoals of different quantities of fish was more difficult when the shoal sizes became more similar. The limit of discrimination ratio was found to be below 2:1. Briefly, angelfish are able to discriminate between different quantities of conspecifics subject to a ratio limit, a finding that implies a fitness component in this behaviour similar to what has been demonstrated in higher order vertebrates.

Previous research into fish welfare has focussed particularly on commercially important aquaculture species. However, with over 350 million fishes traded annually within the ornamental fish industry, surprisingly little consideration has been given to the welfare of fish kept in home aquaria. Here, the welfare of four commonly kept species of ornamental fish (neon tetras, white cloud mountain minnows, angelfish and tiger barbs) was investigated in relation to group size. Behaviours including darting, aggression, shoaling and latency to feed were found to vary with group size in a species-specific manner. Neon tetras and white cloud mountain minnows displayed reduced aggression and darting and spent more time shoaling in larger groups. Behavioural patterns were more variable in angelfish and tiger barbs although larger group sizes resulted in increased shoaling. Principal components analysis of the behaviour scores obtained indicated improved welfare in larger groups of neon tetras, white cloud mountain minnows and tiger barbs with no clear link between welfare and group size in angelfish. In conclusion, although the effect of group size on the behaviour of ornamental fish species is species-specific, combination of behavioural parameters within a principal components analysis allows group sizes that promote improved welfare to be identified.

In this study, the properties and gene expression of the lactate dehydrogenase (EC 1.1.1.27, LDH) isozyme were studied in angelfish (Pterophyllum scalare) - known for their adaptation to the low oxygen environment of the tropics - which were acclimated to acute temperature change () and dissolved oxygen (DO) change () for 2 hours. The properties of the LDH isozymes were confirmed in the native-polyacrylamide gel electrophoresis, Western blot analysis and enzyme activity measurement. Liver- and eye-specific Ldh-C gene were expressed in liver, eye and brain tissues. Through Western blot analysis, the LDH isozyme was shown to have a more cathodal mobility relative to the isozyme. In the liver tissue, the LDH isozyme increased with temperature drop while the isozyme decreased. The LDH and isozymes increased with DO increment, while the isozyme decreased. In the eye tissue, the LDH and B4 isozymse increased with temperature drop while the isozyme decreased. The LDH and isozymes increased with DO increment, but the isozyme and isozymes including the subunit C decreased. In the heart tissue, LDH activity increased with DO increment, as well as the LDH isozyme. In the brain tissue, the LDH and isozymes increased with temperature drop. The LDH isozyme increased with DO increment. Accordingly, since the liver- and eye-specific Ldh-C are influenced by changes in DO and the LDH and isozymes are relatively controlled in the liver and eye tissues, the isozyme can be considered to have a lactate oxidase function.

Made available in DSpace on 2013-08-12T18:18:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-01 Made available in DSpace on 2013-09-30T17:42:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:12:43Z No. of bitstreams: 0 Made available in DSpace on 2014-05-20T13:12:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-01 O objetivo deste estudo foi avaliar o desempenho de acará-bandeira (Pterophyllum scalare) produzidos em diferentes densidades em gaiolas no sistema semi-intensivo instaladas em viveiros em policultivo com camarão-da-amazônia (Macrobrachium amazonicum). Foram testados 4 tratamentos (1; 2; 3 e 4 peixes.10 L-1) em dois viveiros escavados, com 4 repetições cada, em um total de 16 unidades experimentais. Os parâmetros de qualidade de água ficaram dentro do esperado para ambas as espécies. Os dados de desempenho - peso médio, sobrevivência, comprimento padrão, conversão alimentar, fator de condição alométrico, biomassa e uniformidade do lote foram submetidos à ANOVA e as receitas brutas de cada tratamento foram calculadas. Os peixes produzidos na menor densidade apresentaram maiores valores de peso final e comprimento padrão, e menores valores de biomassa em comparação aos demais tratamentos. A conversão alimentar aparente, sobrevivência, uniformidade do lote e fator de condição não apresentaram diferenças significativas entre os tratamentos. A maior densidade testada produziu mais peixes e gerou maior receita bruta do que os demais tratamentos. Portanto, recomenda-se o uso da densidade de 20 peixes.10L-1 para produção comercial de acará-bandeira em gaiolas em viveiro em policultivo com camarão-da-amazônia. The aim of this study was to evaluate the production of Freshwater Angelfish (Pterophyllum scalare) in different stocking densities in cages polycultured with Amazon River Prawn (Macrobrachium amazonicum). Four treatments were evaluated (1; 2; 3 and 4 fish. 10 L(-1)) using two ponds and 24 experimental units. Water quality parameter reached adequate levels for the species. Production data were submitted to ANOVA. Fish produced in the lowest density showed higher values of final weight and standard length, and lower total biomass in comparison with the others treatments. Feed conversion rate, survival, batch uniformity and body factor were not significant different among treatments. The highest density tested produced more fish and gross yield than the others treatments. The density 20 fish. 10L(-1) is recommended to produce Freshwater Angelfish in cages polycultured with Amazon River Prawn. Universidade Federal Rural do Semi-Árido (UFERSA), Dept Ciencias Anim, BR-59625900 Mossoro, RN, Brazil Centro Univ Araraquara, Ctr Univ Araraquara, BR-14801340 Araraquara, SP, Brazil UNESP, Ctr Aquicultira, BR-14884900 Jaboticabal, SP, Brazil Fac Ciencias Agr & Vet, BR-14884900 Jaboticabal, SP, Brazil UNESP, Ctr Aquicultira, BR-14884900 Jaboticabal, SP, Brazil

A freshwater angelfish ( Pterophyllum scalare) hatchery experienced variable levels of emaciation, poor growth rates, swollen coelomic cavities, anorexia, listlessness, and increased mortality within their fish. Multiple chemotherapeutic trials had been attempted without success. In affected fish, large numbers of protozoa were identified both histologically and ultrastructurally associated with the gastric mucosa. The youngest cohort of parasitized fish was the most severely affected and demonstrated the greatest morbidity and mortality. The protozoa were morphologically most consistent with Cryptosporidium. All of the protozoan life stages were identified ultrastructurally and protozoal genomic DNA was isolated from parasitized tissue viscera and sequenced. Histological, ultrastructural, genetic, and phylogenetic analyses confirmed this protozoal organism to be a novel species of Cryptosporidium.

The freshwater angelfishes (Pterophyllum) are South American cichlids that have become very popular among aquarists, yet scarce information on their culture and aquarium husbandry exists. We studied Pterophyllum scalare to analyze dietary effects on fecundity, growth, and survival of eggs and larvae during 135 days. Three diets were used: A) decapsulated cysts of Artemia, B) commercial dry fish food, and C) a mix diet of the rotifer Brachionus plicatilis and the cladoceran Daphnia magna. The initial larval density was 100 organisms in each 40L aquarium. With diet A, larvae reached a maximum weight of 3.80g, a total length of 6.3 cm, and a height of 5.8cm; with diet B: 2.80g, 4.81cm, and 4.79cm, and with diet C: 3.00g, 5.15cm, and 5.10cm, respectively. Significant differences were observed between diet A, and diet B and C, but no significantly differences were observed between diets B and C. Fecundity varied from 234 to 1 082 eggs in 20 and 50g females, respectively. Egg survival ranged from 87.4% up to 100%, and larvae survival (80 larvae/40L aquarium) from 50% to 66.3% using diet B and A, respectively. Live food was better for growing fish than the commercial balanced food diet. Fecundity and survival are important factors in planning a good production of angelfish. Rev. Biol. Trop. 57 (3): 741-747. Epub 2009 September 30.Se realizaron estudios de cultivo en laboratorio del pez ángel, Pterophyllum scalare, para analizar los efectos de su dieta en la fecundidad, crecimiento y sobrevivencia en huevos y larvas por un período 135 días. Tres dietas diferentes se utilizaron A) quistes decapsulados de Artemia, B) comida comercial seca para pez, C) una mezcla de rotíferos, Brachionus plicatilis y el cladocero, Daphnia magna. La densidad inicial de larvas en acuarios de 40L fue de 100 organismos. Utilizando la dieta A, las larvas alcanzaron un peso máximo de 3.80g, una longitud total de 6.3cm y una altura de 5.8cm; utilizando la dieta B, fue de 2.80g, 4.81cm y 4.79cm y con la dieta C, fue de 3.00g, 5.15cm y 5.10cm, respectivamente. Diferencias significativas se observaron entre la dieta A y las dietas B y C. La fecundidad varió de 234 a 1082 huevos en hembras de 20 y 50g, respectivamente. La sobrevivencia de los huevos varió de 87.4% a 100% y la sobrevivencia de las larvas (80 larvas por acuario de 40L) varió entre 50 y 66.3% con las dietas B y A, respectivamente. Los resultados indicaron, que la comida viva fue mejor para el crecimiento de los peces, que los alimentados con la comida comercial balanceada. La fecundidad y la sobrevivencia son factores importantes para la planificación de una buena producción del pez ángel.

Swim bladder non-inflation is common in hatchery-reared fish and was also reported in angelfish, Pterophyllum scalare L. Fish eggs are routinely treated with disinfectants and exposed to a variety of physical conditions. We studied the effect of these factors on the prevalence of swim bladder non-inflation in angelfish. Hatching and rearing at 26 °C resulted in 8% swim bladder non-inflation, compared to no swim bladder non-inflation at 28 °C. Eggs hatched in the presence of 1, 2 and 5 ppm methylene blue exhibited significant increases in swim bladder non-inflation (11, 9 and 33%, respectively; none in controls). Time of exposure to methylene blue was a key factor. Exposure for up to 1 day post-hatch did not affect swim bladder non-inflation, but exposure from 2 days onwards significantly increased swim bladder non-inflation. Hydrogen peroxide at 250 ppm significantly increased swim bladder non-inflation (65% comparing to 27% in the control). Higher concentrations resulted in 100% mortality. Exposure to acriflavin at 2.25 ppm, but not 1.25 ppm, significantly increased swim bladder non-inflation (75 and 52% respectively; 20% in controls). Chloramine-T did not significantly affect swim bladder non-inflation. Treatment with methylene blue and acriflavin, but not chloramine-T, produced significantly different frequencies of swim bladder non-inflation morphologies compared to control fish. In conclusion, several chemical treatments commonly used in aquaculture and sub-optimal water temperature increase the prevalence of swim bladder non-inflation in angelfish.

Debido a la poca información sobre el desarrollo de sistemas orgánicos en el pez Pterophylum scalare (Liechtenstein 1823) estudiamos yiempo neto de desarrollo de cada estadio de la organogénesis, tiempo acumulado y diferenciación de estructuras características de cada estadio. Se obtuvo un total de 8 estadios en la organogénesis del sistema digestivo, comprendidos entre la gástrula y la reabsorción total del saco vitelino. La duración de la organogénesis del sistema digestivo fue de 119 horas 44 minutos.Organogenesis of the digestive system of the fish Pterophylum scalare (Perciformes: Cichlidae). There is little knowledge on the development of the angelfish Pterophyllum scalare (Liechtenstein 1823), a species of economical and biological value for inland water ecosystems. We recorded net development time of each organogenetic stage, cumulative time and characteristic structure differentiation for each stage. We found eight organogenetic stages for the digestive system, between the gastrula and the total re-adsorption of the vitelin sack. The total time for the organogenetic development of the digestive system was 119 hours and 44 minutes. Rev. Biol. Trop. 56 (4): 1857-1870. Epub 2008 December 12.

On the first description of Pterophyllum scalare (Pisces, Cichlidae) The present study reports new data concerning the terra typica (lower Amazon river eastward of Obidos including the lower part of the Rio Tocantins near Cameta), the collector (Friedrich Wilhelm Sieber), and the authorship of the cichlid species Pterophyllum scalare first described as Zeus scalaris (Schultze in Lichtenstein, 1823). The only type specimen still in existence (ZMB 2833) is described and designated as lectotype.

Past research has shown that angelfish, Pterophyllum scalare, are capable of discriminating between shoals composed of familiar dominant and subordinate companions, whereas they show no preference for shoals of unfamiliar conspecifics. In this study, the relative importance of familiarity and social status (shoal factors) on the shoaling decision of juvenile angelfish, which also differed in social status (individual factor), was investigated as very little is known about such tradeoffs in fishes. Dominant and subordinate individuals were given the choice to shoal with a group of conspecifics composed of familiar dominants vs. unfamiliar dominants and composed of familiar subordinates vs. unfamiliar subordinates. The findings demonstrate that fish with different social status differed in their shoaling preference. Subordinate test fish showed a preferential association with familiar subordinates over unfamiliar subordinates, but preferred the unfamiliar shoal over the familiar one when both shoals were constituted by dominant individuals. The shoaling behaviour shown by dominant test fish, on the other hand, indicated no significant preference for any of the shoals regardless of their composition. A replicate preference test carried out 2 h 30 min after the first one indicated that the association pattern was relatively consistent. Results suggest that angelfish are able to differentiate between the stimulus shoals and demonstrate that the pervasive influence of familiarity on the shoaling decision may be restrained or overridden by the composition of the familiar shoals and the social status of the test fish.

Macrophage aggregate (MA) morphometry and pigment composition are believed to be dependent on the species, age, and health status of the fish. The aim of this study was to characterize a "normal" morphometry baseline of spleen and kidney MAs in blue gourami Trichogaster trichopterus and freshwater angelfish Pterophyllum scalare. Three size-classes of clinically normal fish were analyzed. Blue gourami and freshwater angelfish were obtained from three local ornamental fish farms; for each size-class, 10 fish from each farm were analyzed. Hematoxylin- and eosin-stained tissue sections were analyzed by light microscopy at 100x magnification and an image analysis program. The percentage of tissue occupied by MAs, MA size, and MA number were calculated on three arbitrarily selected fields of view from each spleen and kidney. In clinically normal blue gourami, increases in the percentage of tissue occupied by MAs and in MA size were associated with an increase in fish size, but in clinically normal angelfish no correlation was observed. Furthermore, in angelfish, a high variability in MA morphometry was observed, even among fish from the same sample group. In both species, a significant difference in the value of the morphometric parameters was observed among farms. Because iridoviruses inhibit macrophage activity and (possibly) proliferation, MAs in 25 clinical cases of iridovirus-infected blue gourami were analyzed. Preliminary data indicate that in iridovirus-infected blue gourami, there is a decrease in MA size and MA number compared with those of healthy fish.

Angelfish (Pterophyllum scalare) is a very important species in Brazil’s domestic market, enjoying feeding managements that differ from fish breeders to aquarists, so the cost of feed and labor become relevant items when cultivating the species. Thus, the objective of this work was to assess feeding frequency and feed deprivation based on growth performance, parasite infestation and cost-benefit in farming the species. The experiment was conducted in a completely randomized design in a 3x2 factorial scheme with 3 daily feeding levels, 4 meals, 2 meals and 1 meal; with and without feed deprivation and two repetitions. Feed deprivation consisted of offering feed 5 days a week only. Considering the performance, we observed that feeding once a day is the management of choice when the objective is maintaining fish weight. Feeding twice a day without deprivation and four times a day with or without feed deprivation resulted in higher growth performance than feeding once a day. Monogenean and nematode loads were not influenced by feeding management. The cost-benefit analysis enabled us to observe that the treatment with the best benefit was the one involving two feedings a day with no deprivation. Thus, considering the parameters mentioned above, we concluded that the treatment consisting of two daily feedings with no feed deprivation is the most adequate for farming this specie.

Fish of the family Cichlidae are recognized as an excellent model for evolutionary studies because of their morphological and behavioral adaptations to a wide diversity of explored ecological niches. In addition, the family has a dynamic genome with variable structure, composition and karyotype organization. Microsatellites represent the most dynamic genomic component and a better understanding of their organization may help clarify the role of repetitive DNA elements in the mechanisms of chromosomal evolution. Thus, in this study, microsatellite sequences were mapped in the chromosomes of Cichla monoculus Agassiz, 1831, Pterophyllum scalare Schultze, 1823, and Symphysodon discus Heckel, 1840. Four microsatellites demonstrated positive results in the genome of C. monoculus and S. discus, and five demonstrated positive results in the genome of P. scalare. In most cases, the microsatellite was dispersed in the chromosome with conspicuous markings in the centromeric or telomeric regions, which suggests that sequences contribute to chromosome structure and may have played a role in the evolution of this fish family. The comparative genome mapping data presented here provide novel information on the structure and organization of the repetitive DNA region of the cichlid genome and contribute to a better understanding of this fish family's genome. © Carlos Henrique Schneider et al.

Pterophyllum scalare belongs in the family Cichlidae of Cichliformes. This species and its congeners are characterized by a compressed and disc-shaped body with dorsal and anal spiny rays increasing in length from anterior to posterior part of the fin. In this study, we determine and describe the complete mitogenome sequence of Pterophyllum scalare for the first time, which is 16,494 bp in length, and contains 37 genes, including 13 protein-coding genes, 2 rRNAs, 22 tRNAs, 1 origin of replication on the light-strand (OL) and a putative control region. The overall base composition is 27.5% A, 26.8% T, 30.1% C and 15.6% G, with a slight AT bias (54.3%). All protein-coding genes share the start codon ATG, except for COI that begins with GTG. These results are expected to provide useful molecular data for phylogenetic studies of Cichlidae and Cichliformes. Maximum Likelihood (ML) tree and Bayesian analyses based on partitioned nucleotide sequences of 12 mitochondrial protein-coding genes were constructed and both yielded trees with identical topologies.

Summary The length–weight relationships (LWRs) of 11 freshwater fish for eight families (Leporinus friderici, Pterophyllum scalare, Geophagus camopiensis, Curimata incompta, Astyanax bimaculatus, Tetragonopterus chalceus, Moenkhausia lepidura, Metynnis lippincottianus, Plagioscion squamosissimus, Hemiodus unimaculatus and Colomesus asellus) captured in tributary of the Amazon River system (Brazil) were investigated. These results represent the first reference on the LWRs for all 11 species in the eastern Amazon.

Time-place learning based on food association was investigated in the cichlids angelfish (Pterophyllum scalare) and pearl cichlid (Geophagus brasiliensis) reared in isolation, therefore eliminating social influence on foraging. During a 30-day period, food was placed in one side of the aquarium (containing three compartments) in the morning and in the opposite side in the afternoon. Learning was inferred by the number of correct side choices of all fish in each day of test (15th and 30th). During the test day fish were not fed. The angelfish learned to switch sides at the correct day period in order to get food, suggesting this species has time-place learning ability when individually reared. On the other hand, the same was not observed for pearl cichlid.

Neste estudo, avaliaram-se as exigências nutricionais de proteína para alevinos de acará-bandeira. O delineamento experimental utilizado foi o inteiramente casualizado, com quatro tratamentos (34, 38, 42 e 46% de PB) e quatro repetições. Alevinos (0,44 ± 0,05 g) foram distribuídos em 16 aquários com volume individual de 25 L, dotados de sistema de filtragem, aeração e controle de temperatura (26 ± 0,5ºC), em densidade de estocagem de seis peixes/aquário, onde foram alimentados à vontade, às 8, 11, 14 e 17 h, durante 60 dias. Os parâmetros de desempenho produtivo avaliados foram: peso final, ganho de peso, consumo de ração, conversão alimentar, taxa de crescimento específico e taxa de eficiência protéica (TEP). Ao final do experimento, não foi observado efeito significativo dos tratamentos sobre o desempenho produtivo, exceto para a TEP. A dieta com 46% de PB resultou em TEP significativamente menor que as dietas com 34 e 38% PB, enquanto a dieta com 42% de PB não diferiu das demais. Dietas contendo 34% de PB atendem às exigências nutricionais em proteína de alevinos de acará-bandeira. The aim of this experiment was to evaluate dietary protein requirements of freshwater angelfish fry. A complete randomized design with four dietary crude protein levels (34, 38, 42, and 46% of CP) and four replicates was used. Fish averaging 0.44±0.05 g were reared in sixteen 25L-aquarium with aeration, biological filter and controlled temperature (26 ± 0.5°C), in a stocking density of six fish/aquarium. Fish were fed ad libitum at 8:00 a.m., 11:00 a.m., 2:00 p.m, and 5:00 p.m, during 60 days. Final weight, weight gain, feed intake, feed:gain ratio, specific growth rate and protein efficiency ratio (PER) were the evaluated parameters of productive performance. At the end of the experiment, no treatment effect on productive performance, with the exception of PER was observed. Fishes fed diets with 46% CP showed PER significant smaller than those fed diets with 34 and 38% of CP. PER of fish fed diets with 42% of CP did not differ from the other treatments. Diets with 34% of CP can meet the protein nutritional requirements of freshwater angelfish fry.

Previous experiments have shown that angelfish are capable of discriminating between shoals composed of conspecifics of different social status and that familiarity mediates the decision. In the present work, the shoaling behaviour of dominant and subordinate angelfish, Pterophyllum scalare, was again examined and the role that potential behavioural differences between the stimulus shoals may play in the shoaling decisions was investigated. In binary shoal choice tests, the stimulus shoals were composed of dominant and subordinate conspecifics from the same dominance hierarchy as the test fish but, in contrast with most studies of this type, the stimulus shoals were placed in tanks that allowed for the full expression of behavioural patterns. Test fish, regardless of social status, showed an association preference for a shoal of dominant over a shoal of subordinate conspecifics. The tendency was significant in the second observation period, which took place about 2 hr and 30 min after the first one, when ...

O experimento foi conduzido na Universidade Estadual Paulista, Laboratório de Peixes Ornamentais do Centro de Aqüicultura da Unesp, Jaboticabal, Estado de São Paulo, com o objetivo de avaliar o desempenho produtivo do acará bandeira (Pterophyllum scalare), alimentados com dietas processadas de três formas (farelada, peletizada e extrusada). Foram utilizados 240 peixes distribuídos em 24 aquários de 40 L, alimentados com uma dieta contendo 28% de PB e 4000 kcal kg-1 de EB. Avaliou-se o peso final médio, ganho de peso, taxa de crescimento específico, consumo de ração e conversão alimentar. Ao final de oito semanas, não houve diferença significativa no desenvolvimento dos peixes alimentados com dietas extrusada e peletizada. Os alimentados, entretanto, com dieta farelada apresentaram baixa taxa de crescimento específico. A taxa de conversão alimentar foi melhor em indivíduos alimentados com dieta extrusada. Nas condições presentes neste estudo dietas extrusadas e peletizadas são adequadas para o crescimento e manutenção do acará.The experiment was conducted in the Laboratory of Ornamental Fish at the Aquaculture Center of Unesp, State of São Paulo, Brazil, aiming to evaluate the growth performance of the angelfish (Pterophyllum scalare) fed with three different diets (pelleting, extruding and grinding). Two hundred forty fish were stocked in 24 aquaria (40 L) and fed with a diet of 4000 kcal kg-1, crude energy and 28% crude protein. The final mean weight, weight gain, specific growth rate, feed intake and feed conversion were evaluated. After 8 weeks there was no difference on angelfish fed with extruded and pelleted diet. However fish fed with grinded diet presented poor growth and the specific growth rate was smaller. The feed conversion ratio had better values in fish fed with extruded diet. It was concluded that both extruded and pelleted diets were suitable for growth and maintenance of angelfish.

In previous studies, we found that rapidly confined hybrid striped bass ( Morone saxatilis male× Morone chrysops female) developed a syndrome characterized by the immediate and dramatic loss of their skin. We have named this phenomenon the Acute Ulceration Response (AUR). AUR is characterized by the rapid onset of severe epidermal degeneration, erosion, and ulceration on the body skin and fins, as well as corneal ulceration, in stressed hybrid striped bass. In the present study, we have shown that acute confinement stress can also cause AUR in a taxonomically wide array of fish species, including guppy ( Poecilia reticulata ), freshwater angelfish ( Pterophyllum scalare ) and channel catfish ( Ictalurus punctatus ) after a 2-h stress. However, we could not induce AUR in rainbow trout ( Oncorhynchus mykiss ). The AUR lesions were similar to those seen previously in hybrid striped bass. As AUR might be expected to predispose fish to secondary microbial infections, we examined the skin of hybrid striped bass for bacterial infection after experimental induction of AUR. These experiments showed that even fish with severe skin damage could rapidly heal their wounds without obvious consequences within several days. Bacterial numbers in AUR lesions remained low, ∼10 4 cfu/g of fin tissue, throughout the recovery period. However, if hybrid striped bass with AUR were exposed to even low doses (1 zoospore/ml) of the water mold Saprolegnia , a relatively weak, opportunistic pathogen, the fish developed severe saprolegniosis as soon as 48 h after challenge, with 87.5% infected and 87.5% dead within 4 days post-challenge. In contrast, none of the control fish (no AUR, but exposed to Saprolegnia ) developed saprolegniosis. These data provide strong evidence that AUR might play a critical role in skin ulcer epidemics of many fish species that are preceded by an acute stress. Furthermore, our data suggest that environmental pathogen load plays a critical role in determining if AUR lesions will heal spontaneously or instead will lead to devastating disease losses.

[Shoal choice studies have revealed that fish have cognitive abilities to discriminate between groups of different composition. In this work, the role of social status (based on aggressive acts) of both the test fish and the fish in the stimulus shoals was examined because of the fitness-related consequences that group association may have for the test individual. Single angelfish of high and low social status (dominant and subordinate) were presented with a choice between two stimulus shoals composed of three conspecifics of equal size and familiarity but of social status equal to, and different from that of the test fish in the same dominance hierarchy. Test fish, irrespective of the social status, spent significantly more time shoaling with subordinates than with dominants. They also initiated shoaling behaviour with subordinates more readily and the number of visits to the preference zone close to the subordinates was greater than that to dominants. The tendency was greater in subordinate fish, which showed longer latency in approaching the shoals of dominants, and spent more time in proximity to the subordinates per visit than did dominant fish. A replicate preference test indicated that this general pattern was relatively stable for at least 2f hr. A possible factor mediating this association preference, that of familiarity, was then tested. The same protocol as before was used but unfamiliar conspecific dominants and subordinates served as stimulus shoals. In this second experiment, generally test fish did not show any significant shoaling preference. The results indicate that angelfish are capable of distinguishing the social status of conspecifics and can discriminate between shoals composed of dominants and subordinates on the basis of previous interactions. It is suggested that the tendency to avoid shoals of dominant companions may be due to the disadvantage of enhanced competition, subordinates being more affected., Shoal choice studies have revealed that fish have cognitive abilities to discriminate between groups of different composition. In this work, the role of social status (based on aggressive acts) of both the test fish and the fish in the stimulus shoals was examined because of the fitness-related consequences that group association may have for the test individual. Single angelfish of high and low social status (dominant and subordinate) were presented with a choice between two stimulus shoals composed of three conspecifics of equal size and familiarity but of social status equal to, and different from that of the test fish in the same dominance hierarchy. Test fish, irrespective of the social status, spent significantly more time shoaling with subordinates than with dominants. They also initiated shoaling behaviour with subordinates more readily and the number of visits to the preference zone close to the subordinates was greater than that to dominants. The tendency was greater in subordinate fish, which showed longer latency in approaching the shoals of dominants, and spent more time in proximity to the subordinates per visit than did dominant fish. A replicate preference test indicated that this general pattern was relatively stable for at least 2½ hr. A possible factor mediating this association preference, that of familiarity, was then tested. The same protocol as before was used but unfamiliar conspecific dominants and subordinates served as stimulus shoals. In this second experiment, generally test fish did not show any significant shoaling preference. The results indicate that angelfish are capable of distinguishing the social status of conspecifics and can discriminate between shoals composed of dominants and subordinates on the basis of previous interactions. It is suggested that the tendency to avoid shoals of dominant companions may be due to the disadvantage of enhanced competition, subordinates being more affected.]

Thirty-five aquarium fish were investigated for the presence of mycobacteria by culture and molecular methods. The following species were examined: goldfish Carassius auratus auratus, guppy Poecilia reticulata, 4 three-spot gourami Trichogaster trichopterus, dwarf gourami Colisa lalia, Siamese fighting fish Betta splendens, freshwater angelfish Pterophyllum scalare, African cichlid fish Cichlidae spp., cichlid fish Microgeophagus altispinosus, cichlid fish Pseudotropheus lombardoi, blue streak hap Labidochromis caeruleus, sterlet Acipenser ruthenus, southern platyfish Xiphophorus maculatus, and catfish Corydoras spp. Isolates of mycobacteria were obtained in 29 cases (82.9%). Two specimens were positive using Ziehl-Neelsen (ZN) staining, but the cultivation failed. Four specimens were both ZN- and culture-negative. On the basis of GenoType Mycobacterium assay (Hain Life-science) and restriction enzyme analysis of the amplified products (PCR-RFLP), 23 isolates (79.3%) were identified: 7 as Mycobacterium fortuitum, 6 as M. gordonae, 6 as M. marinum, 3 as M. chelonae, and 1 as M. peregrinum. Five isolates remained unidentified (Mycobacterium spp.). One case probably represented a mixed infection (M. marinum/M. fortuitum). Since M. marinum infections are also detected in humans, the significance of mycobacteria in aquarium fish should not be overlooked.