Search

Buyan Lake has some fishery commodities which were often encountered include the Zebrafish (Amatitlania nigrofasciata). The origin existence of Zebrafish in Buyan Lake is not yet known then it needs study in order to know the certainty of species, phylogenetic, haplotype diversity, and phenotype characteristic. The study was conducted from January to February 2018. Molecular identification was done at Laboratory of Biodiversity Indonesia Bali. This research used quantitative and qualitative descriptive methods. Sampling was done by simple random sampling from fisherman catches. Zebrafish’s fin samples were used for molecular identification and Zebrafish’s morphological for morphological identification. The results showed that the entire sequence samples were successfully amplified with the Cytochrome Oxidase subunit I (COI) gene of 620 bp. The genetic distance in the entire Zebrafish sequences in Buyan Lake of 0 which means that the sequence of all samples are exactly similiar as species of Amatitlania nigrofasciata with the genetic distance calculation of 0. Sequence of Zebrafish in Buyan Lake is closely related to Amatitlania nigrofasciata KU568740, Amatitlania nigrofasciata KU568739, Amatitlania nigrofasciata KU568737, Amatitlania nigrofasciata KJ552531, and Amatitlania nigrofasciata KU568738 with genetic distance of 0 and has a distant relation with Rocio ostofasciata EU751752 with genetic distance of 0.113. The haplotype diversity of Zebrafish sequences in Buyan Lake showed the value of 0 which belongs to a low haplotype diversity. Black and Black Zebrafish with Red Spotted are in a different clade with Albino and Albino Zebrafish with Red Spotted with bootstrap value of 100, means they have phenotypically differences.

Introduction of non-native species is a problem worldwide. Local populations of the Mexican mojarra, Cichlasoma istlanum, have been hypothesized to be negatively affected by the introduction of the convict fish, Amatitlania nigrofasciata. The Mexican mojarra is a cichlid fish native to the Balsas-River Basin. As a first approach to understand the behavioral effect of the convict fish on Mexican mojarra, we experimentally studied the behavioral responses of the latter when exposed to the former. Thus, we recorded refuge use, swimming activity and feeding rate of Mexican mojarra in the presence of a convict fish, a conspecific, and alone. Mexican mojarra used refuges for longer, swum for shorter and ate less in the presence of convict fish than with conspecifics or alone. Because prolonged use of refuge habitat may deprive Mexican mojarra of opportunities to feed, grow, and reproduce, we hypothesize that convict fish can negatively affect the fitness of the former where the two species co-occur.

Parents jointly defend their pair-bond against females that are potential mates for the male but sexual rivals for the females. We experimentally exposed breeding pairs of convict cichlids to conspecific females that differed in their reproductive state, advertised via conspicuous ornamentation. We found parental females responded aggressively to reproductive females and that parental males also behaved aggressively, particularly when mated to smaller females. These results suggest cooperation, not conflict, between parents to address potential pair-bond threats.

Bu çalışmada zebra çiklit (Amatitlania nigrofasciata) ventrikülünün morfolojik ve histolojik özellikleri ışık mikroskobu ile incelenmiştir. Ventrikül, piramit biçimlidir ve ventrikül duvarı epikardiyum, miyokardiyum ve endokardiyum tabakalarından meydana gelmiştir. Epikardiyum ve endokardiyum tek katlı yassı epitel ile ince bir bağ dokudan oluşmuştur. Daha kalın bir tabaka olan miyokardiyum, kolayca ayırt edilebilen iki tabaka halinde izlenmiştir; dış tabaka, sıkı şekilde organize olmuşken iç tabaka, dallanmış kalp kası demetleri arasında yer alan iri trabekülleri ile süngerimsi görünüme sahiptir. Ventrikülün piramidal biçimi ve kas düzenlenişi metabolik aktivitenin önemli bir parametresi olarak değerlendirilerek tartışılmıştır., The morphological and histological structures of the ventricle of convict cichlid (Amatitlania nigrofasciata) were described light microscopically. The ventricle was pyramidal in shape, and its wall was comprised of epicardium, myocardium, and endocardium. Epicardium and endocardium were thin and had similar histological structure that consisted of simple squamous epithelium and connective tissue. The thicker layer, myocardium, was composed of two layers differentiated easily: the outer part was compactly organized while the inner one was observed as spongy in appearance with large trabeculae oriented between branched bundles of cardiac muscle. The pyramidal shape and myoarchitectural features of the ventricle were evaluated and discussed as being the most important histological parameter of metabolic activity which is depended on myocardial functions.

Territoriality and the factors that influence the outcome of animal contests are easy to study in a lab using convict cichlid fish (Archocentrus nigrofasciatus). I present a two-week laboratory experiment suitable for high school and college students. In the first week, students observe resident and intruder convict cichlids interacting in the presence of flowerpot territories, allowing them to develop hypotheses about factors that might determine the outcome of contests over resources, including relative size of competitors (“resource holding potential” hypothesis) and ownership (“resource value” hypothesis). They then work with their teacher to design and set up an experiment to test these two hypotheses, providing specific predictions that would support each hypothesis. In the second week, students observe contests between each owner and a larger or smaller intruder. The winner is defined as the individual that spends the most time in the pot and bites more. Students graph their data and decide what statistics are most appropriate for analyzing their results. They determine which hypothesis is supported by their findings and present their findings in scientific paper format.

For species in which individuals spend at least some time in groups, dominance relationships and various social cues are often important for mate assessment and choice. For pair bonding species, social experiences may affect reproductive decisions in both sexes. We tested whether prior experience in a mixed-sex group and having a higher dominance status coincides with faster pair formation or spawning in a monogamous fish. Individuals having prior experience in mixed-sex groups paired with a novel fish more frequently than fish from same-sex groups. Fish in mixed-sex groups performed more bites and lateral displays. Although spawning occurred infrequently across pairs, dominant fish from mixed-sex groups spawned more than dominant fish from same-sex groups. Otherwise, there were no clear behavioural relationships between treatment group and subsequent pair formation or spawning, nor were behaviours of the paired fishes related to their prior treatment group. We do not know how mixed-sex social experience may have affected the physiology of those individuals, although our results support a reproductive priming effect.

9 pages; International audience; In monogamous species, partner compatibility is a key factor influencing pairing and reproductive success. In pairs with biparental care, studies have mostly focused on behavioral compatibility because it is likely to encourage the coordination of parental care within pairs, leading to a better reproductive success. Behavior modulation, throughout the breeding season and as a function of the social context, is under the regulatory feedback control of endocrine mechanisms. From this link, the idea of hormonal partner compatibility as a key component of pair cohesion and maintenance has recently emerged. Here, we investigated the link between partner behavioral assortment and their hormonal response to the pairing context. We formed assortative and disassortative pairs of convict cichlids based on their behavioral type (proactive or reactive) and took hormone and fitness measurements. Testosterone, 11-ketotestosterone, 17β-estradiol and cortisol levels were measured from fish-holding water before and after pair formation. We found no relationship between the behavioral type of individuals and their pre-pairing hormone levels. Only the level of cortisol was affected by the partner but independently of its behavioral type. Reproductive success was not affected by the level of hormonal similarity within pairs, but we found that the variation in 11-ketotestosterone similarity between the isolated context and the pairing context was related to spawning size, and the variation in cortisol similarity to the number of fry. Behavioral compatibility does not reflect hormonal compatibility in the convict cichlid, but the relationship between reproductive success and the flexibility of hormonal similarity between partners suggests hormonal adjustment within pairs in this species.

The aim of model experiments were tracking temporal dynamics of breathing intensity tsyhlazoma aquarium fish-zebra (Amatitlania nigrofasciata) at the action of toxicants in different concentrations to determine the approximate levels of assess and the degree of toxicity of the aquatic environment. Fisheries regulations (maximum allowed concentration), caused using various concentrations of substances which are the most common contaminants of the aquatic environment. Fish respiration was assessed by difference in content of dissolved oxygen every 0.5 hrs during the exposure of individuals in the corresponding solution toxicants. The oxygen concentration was measured using instrumental method. As a test parameter coefficient of respiration fish was used. The rate was calculated as the ratio of test reactions version of the experiment and the control. The accuracy of the measu­rements was assessed by the closeness of approximation between the experimental data. The reliability levels of control deviation for each time interval of exposure was tested by Fisher criterion. Statistical rankings of experimental data was carried out within five groups, as recommended by the EU Water Framework Directive regarding the development of the rating scales of ecological state of the aquatic environment. The level of coefficient of fish respiration was ≤50.8 % as recorded in variants of experiment with concentrations of most chemicals at 10 MAC and certain substances at 5 MAC, which was seen as a manifestation of critical toxicity of the aquatic environment for fish. The coefficient of fish respiration within 51.1–101.6% were recorded in some embodiments experiment with concentrations of chemicals at 2 maximum allowed concentration, 3 maximum allowed concentration and 5 maximum allowed concentration, indicating high toxicity. The coefficient of fish respiration 101.7–52.4 % were recorded in variants with concentrations of certain substances at 2, 3 and 1 concentration, which may indicate a moderate or high toxicity. Indicators within 152.5–203.2 % – variations in the concentrations of certain substances at 0.5 concentration, 1 concentration and 2 concentration which was seen as evidence of a weak environment of toxicity to fish. The coefficient of fish respiration ≥203.2 % were recorded 0.5 maximum allowed concentration and 1 concentrations of substances, that was seen as a lack of toxicity. Thus, the methodology of toxicity bioassay of water environment in terms of the intensity of fish respiration, was improved namely: optimal exposure A. nigrofasciata aquarium fish in the experimental samples of water; specified formula of fish respiration intensity during the experiments; proposed indicative scale integrated assessment of the toxicity degree in the aquatic environment. This speeds to obtaining of the integra­ted response of the toxicity of water environment with the ability to reuse test objects.

This study evaluated the effects of diet containing 0 (C: control), 75 (D1), 100 (D2), 125 (D3) and 150 (D4) mg kg−1 F. vulgare essential oil on growth and reproductive performance of C. nigrofasciatum. A total of 225 Convict cichlids female with mean weight (1.65 ± 0.02 g) were distributed into 15 glass aquaria (15 fish tank−1) in triplicate treatments. During 40 days of experimental period, fish fed at 3% of their body weight daily. At the end of experiment, growth indices, gonadosomatic index and reproductive indices were determined. The best feed conversion ratio was obtained in D4 (1.19 ± 0.03, P 0.05). F. vulgare essential oil has no negative effect on survival rate of C. nigrofasciatum. There were no significant differences among protein content of fish body (P > 0.05). The lowest value of fat content (26.5 ± 0.5%) was observed in D2, and it had significant difference with control and other groups (P 0.05).

In humans, affective states are a key component in pair-bonding, particularly in the early stage of a relationship. Pairing with a high-quality partner elicits positive affective states which, in turn, validate and reinforce the mate choice. Affective states thus strongly affect pair stability and future reproductive success. We propose generalizing the link between affective states and pair-bonding to encompass other monogamous species exhibiting biparental care, chiefly where the reproductive success of the pair critically depends on the coordination between partners. The convict cichlid Amatitlania siquia is a monogamous fish species that forms long-lasting pairs with strong cooperation between parents for parental care. In this species, we showed that females paired with their non-preferred male had lower reproductive success than those paired with their preferred male. We then transposed the judgement bias paradigm, previously used in other animal species, to assess objectively affective states in fishes. Females that were assigned their non-preferred partner exhibited pessimistic bias, which indicates a negative affective state. By contrast, females that were assigned their preferred partner did not exhibit changes in their affective state. Our results highlight that the influence of pair-bonding on affective states is not human-specific and can also be observed in non-human species.

Monogamy can be either long-term or serial, with new pairs formed with each breeding bout. Costs and benefits are associated with each strategy. Because biparental convict cichlids (Amatitlania nigrofasciata) typically switch mates, exhibiting serial monogamy, we tested for the costs associated with forcing individuals to remain with the same mate. Convict cichlids were observed over two successive breeding bouts, either with the same or a new, equally experienced, mate. Parental behavior did not differ between breeding bouts, nor did brood size. Surprisingly, fish that remained with their original partner for a second bout took significantly longer to produce a brood compared to fish that paired with new partners. New partners were also more likely to successfully produce a second brood than re-mated partners. This is in contrast to the majority of bird studies that show many benefits to staying with the same partner for multiple broods. In convict cichlids, there seems to be no benefit associated with remaining with the same partner and switching mates reduces duration between broods for both males and females, potentially increasing overall reproductive success.

We investigated the trophic transfer potential of CuO-NPs from Artemia salina to Amatitlania nigrofasciata. The Cu uptake was investigated by exposure of the instar II nauplii to 0, 1, 10, and 100 mg/L CuO-NPs for 4 h. Dietborne exposure of fish larvae to CuO-NPs was done for 21 days through feeding with pre-exposed nauplii. Thereafter, all survived fish were fed for 21 more days with non-contaminated nauplii. The results showed that NPs could be taken up by nauplii in a concentration-dependent manner. The highest uptake of Cu by nauplii was found to be 50.5 ± 1.4 mg/g dry weight at 100 mg/L. The copper accumulation in fish larvae increased significantly with increasing Cu content in pre-exposed nauplii to different concentrations of CuO-NPs (p

Many monogamous species demonstrate size-assortative mating patterns within natural populations. To better understand the role of intersexual selection in this process, we examined the effect of male preference for female body size in the convict cichlid (Amatitlania siquia). We provided males with a choice between females that differed in size, relative to each other and in relation to the focal male. Based on previous work, we expected males to prefer the largest available female mates across all treatments. Surprisingly, males spent more time near the smaller of two available females, but only when the other female was larger than the male. Additionally, males spent little time with either of two potential female mates when both females were larger than the male. We hypothesized that while males might prefer the largest of available females, female behavior might limit males from acting on this preference. To test this, males were force paired with a smaller or larger female. Pair formation only occurred when the female was smaller than the male, and females that were larger than their male counterparts showed significantly more aggression when compared to smaller females. Together, these data suggest that in the absence of intrasexual competition, male mate preference for large females in convict cichlids might be limited by female aggression.

Recent studies have documented that exposure to high levels of background risk can induce neophobic predator avoidance in prey animals, whereby they respond to any novel cue with an anti-predator response. Such phenotypically plastic predator avoidance may allow prey to maximize anti-predator benefits in variable risk environments. It remains poorly understood whether risk assessment information from different sensory modalities can be integrated to induce generalized, cross-sensory system neophobic responses. Here, we directly test this hypothesis by exposing juvenile convict cichlids (Amatitlania nigrofasciata) to high- versus low-risk environments using either conspecific alarm cue (chemosensory risk) or a model avian predator (visual/mechanical risk) and testing their response to a novel chemosensory cue (Experiment 1) or visual cue (Experiment 2). Our results suggest that regardless of the sensory modality used to increased perceived risk, cichlids pre-exposed to high-risk conditions exhibited increased predator avoidance in response to any novel visual or chemical cue. As expected, cichlids pre-exposed to low-risk conditions did not display any neophobic responses. Our results suggest that induced neophobia is not cue specific; rather, it may function as a generalized response to perceived predation risk.

Numerical abilities have been found to be adaptive in different contexts, including mating, foraging, fighting assessment and antipredator strategies. In species with parental care, another potential advantage is the possibility to adjust parental behavior in relation to the numerosity of the progeny. The finding that many fish vary their parental investment in relation to brood size advocates the existence of a mechanism for appraising offspring number, an aspect that has never been directly investigated. Here we tested the ability of parental female convict cichlid (Amatitlania nigrofasciata) to discriminate between two fry groups differing in number by measuring time spent attempting to recover groups of fry experimentally displaced from the next. Females spent more time trying to recover the fry from larger groups when tested with contrasts 6 versus 12 (1:2) and 6 versus 9 fry (2:3); however, they showed no preference in the 6 versus 8 (3:4) contrast, suggesting that this task exceeds their discrimination capacity.

An 8-year-old female convict cichlid ( Amatitlania nigrofasciata ) was presented to the University of Wisconsin Veterinary Medical Teaching Hospital with a 2-month history of abnormal buoyancy; the fish spent most of its time in lateral recumbency on the aquarium substrate. During the initial visual examination of the patient in its transport aquarium, the fish was laterally recumbent on the bottom of the tank and had a mildly distended coelom. A transient response to empirical florfenicol therapy was reported, but the cichlid presented 1 month later in poor body condition and, again, in lateral recumbency. Owing to the poor prognosis, the fish was humanely euthanized and a necropsy was performed. The histopathologic results were consistent with a papillary carcinoma originating in the ovary, which invaded the caudal kidney and the swim bladder. The infiltration of the carcinoma into the swim bladder was suspected to be the primary cause of the clinically observed buoyancy abnormality.

Female convict cichlids (Amatitlania siquia) exhibit bright orange ventral coloration that males lack. The behavioral implications of this color are poorly understood, particularly in naturally occurring populations where female coloration could play a role in the expression of territorial nest-guarding behaviors. In this field experiment, monogamous breeding pairs of convict cichlids were presented with 3D printed model conspecific intruders of three body sizes (small, medium, and large) exhibiting three orange patch sizes (large, small, or none) to observe how territorial aggression varied as a function of intruder size and female coloration. Individuals occupying breeding pairs that were defending hatched offspring were significantly more aggressive toward intruders with small and large amounts of orange than toward models lacking orange, indicating that color is an important context-dependent elicitor of aggression in this species. Males were significantly more aggressive toward the intruder than females, and male aggression was strongly influenced by their size relative to the intruder. When males were smaller than the intruder, they performed significantly more aggressive acts than when they were the same size or larger than the intruder; this trend persisted across three putative populations in Lake Xiloa, Nicaragua. A potential explanation for these findings is that the orange color functions as a signal of individual quality or breeding readiness and that breeding pairs increase aggression to repel intruders that pose the greatest threat to pair bond and nest maintenance. One or both sexes of many animal species possess brightly colored features that might communicate information about overall heath or reproductive status. In convict cichlid fish, males and females establish pair bonds and jointly defend their nest and offspring. Single females exhibit striking orange coloration that males and breeding females lack. Our field-based experiment provided evidence that more colorful females, which likely pose a threat to pair bond stability and nest maintenance, incite more aggression from breeding pairs than drab females. Our study suggests that color provides salient information about, perhaps, female quality or readiness to breed in natural populations, and adds to a growing body of research that seeks to understand the varied roles that colorful ornaments play in animal communication.

This study explored whether convict cichlid fish mount a hormonal response to aggressive encounters where dominance status remains unresolved. Hormone samples were collected at two time points before an aggressive interaction to obtain confinement-induced and baseline measures, and at one time point following a contest across a clear partition (experimental) or exposure to an opaque partition with an opponent on the opposite side (control). There was no overall significant effect of treatment (control vs. experimental) on hormone release rates but there were trends for cortisol and testosterone (T). A priori linear contrasts showed that individuals that engaged in aggressive interactions had lower postfight cortisol and T release rates than controls, suggesting that aggression, in this context, might attenuate the synthesis of both hormones. Cortisol decreased significantly between initial confinement and baseline, indicating that individuals habituate to the water-borne hormone collection procedure. Contrary to expectation, individuals with higher baseline T and 11-ketotestosterone (KT) release rates took longer to initiate conflict. None of the other measures of behavior were predicted by baseline hormone release rates, and contest behavior did not predict postfight hormone release rates. There was a significant positive relationship between KT and T at all time points. As with studies that employ mirror image stimulation, we found no hormonal response to unresolved contests despite high levels of aggressive behavior. Our study is unique because we demonstrate that animals engaged in conflict with live opponents also do not mount a significant hormonal response when clear dominance relationships are not established.

A behavioral syndrome is considered present when individuals consistently express correlated behaviors across two or more axes of behavior. These axes of behavior are shy-bold, exploration-avoidance, activity, aggression, and sociability. In this study we examined aggression, boldness and sociability (shoaling) within a juvenile convict cichlid brood (Amatitlania nigrofasciatus). Because young convict cichlids are social, we used methodologies commonly used by ethologists studying social fishes. We did not detect an aggression-boldness behavioral syndrome, but we did find that the aggression, boldness, and possibly the exploration behavioral axes play significant roles in shaping the observed variation in individual convict cichlid behavior. While juvenile convict cichlids did express a shoaling preference, this social preference was likely convoluted by aggressive interactions, despite the small size and young age of the fish. There is a need for the development of behavioral assays that allow for more reliable measurement of behavioral axes in juvenile neo-tropical cichlids.

In the present study, the effects of dietary supplementation with polyphenols extracted from agricultural by-products were investigated on serum and/or skin mucus antioxidant and immune responses, and hematological parameters of the convict cichlid (Amatitlania nigrofasciata). Polyphenols extracted from chestnut wood (CW) and olive mill waste water (OMWW) were provided as a mixture (PMIX) (9:1, CW:OMWW). PMIX concentrations of 0.5, 1.0 and 2.0 g/kg of diet were employed. Fish were stocked in 12 tanks and fed with the enriched diets for 8 weeks. After the 8-week period, serum total protein, lysozyme, total immunoglobulins (Ig), catalase (CAT) and radical scavengering activity (RS), skin mucus total protein, total Ig and peroxidase activity, and blood hematological parameters were determined. The results showed that, regardless of inclusion level, skin mucus total Ig and lysozyme activity were significantly increased in the PMIX-treated fish compared to control. The most pronounced changes were related to the supplementation with 2.0 g/kg of PMIX. Similar results were noticed in cases of serum total protein and total Ig. Serum RS and peroxidase activity the fish receiving the 2.0 g/kg PMIX treatment were significantly higher than the other treatments. However, there were no significant differences in the activities among the other treated groups. Serum CAT activity of the fish in the 2.0 g/kg PMIX treatment was significantly higher than the other treatments. Serum CAT activity of the fish in 1.0 g/kg PMIX was significantly higher than the control group, but there were no significant differences in the serum CAT activity between the control and 0.5 g/kg PMIX treatments. There were no significant difference in blood RBC, hematocrit and MCV values among the treatments. In conclusion, PMIX at 2.0 g/kg markedly improves humoral and mucosal immune responses and serum antioxidant responses of the convict cichlid, effects that are probably related to the antioxidant and health-promoting nature of PMIX. Therefore, 2.0 g/kg PMIX is recommended as dietary inclusion levels to increase the overall health of convict cichlid.

The Mesoamerican cichlids display a spectacular diversity of pigment patterns, which serve a variety of functions and serve as a strong selective trait for this lineage. The development and variation of coloration in the Mesoamerican cichlids have been detailed by several groups. In particular, Řican, Musilova, Muska, and Novak () and Řican, Pialek, Dragova, and Novak () determined homology of pattern and revealed four alternative types of coloration and their ontogeny. In this work, this group posed an "ontogenetic timing hypothesis" proposing heterochronic shifts underlying major transitions in the evolution of the Mesoamerican cichlids. Here, we experimentally test this hypothesis by experimentally altering timing of pigment pattern formation in the convict cichlid Amatitlania nigrofasciata, a member of the Mesoamerican cichlids, via manipulations of thyroid hormone (TH) function. The response of different pigment cell lineages to TH-perturbations revealed that the transition from larval to juvenile coloration in the convict cichlid is under the control of TH-signaling. Importantly, hormonally induced changes in the timing of pigment cell lineages' development resulted in shifts of coloration ontogeny type observed between lineages and led to the appearance of phenotypes mimicking those in phylogenetically close and distant species. Thus, our findings support the hypothesis that simple changes in ontogenetic timing underlies species specific patterns in pigmentation and provide new perspectives for studying the role of endocrine signaling in the evolution of cichlids.

Successful territory defence is a prerequisite for reproduction across many taxa, and often highly sensitive to the actions of territorial neighbours. Nevertheless, to date, assessments of the significance of the behaviour of heterospecific neighbours have been infrequent and taxonomically restricted. In this field study, I examined the importance of both heterospecific and conspecific neighbours in a biparental fish, the convict cichlid, Amatitlania siquia. This was done by assessing the colonisation rates of vacant territories, the rates of aggression by the territory holders, and the overall rates of aggression towards intruders, in treatments that controlled the proximity of both neighbour types. Convict cichlid pairs colonised vacant nesting resources (territory locations) at similar rates independent of the proximity of heterospecific (moga, Hypsophrys nicaraguensis) or conspecific neighbours. However, a model of sympatric cichlid intruder was subjected to considerably higher overall levels of aggression when mogas were nearby. In contrast, the proximity of conspecifics did not have a significant effect on the overall aggression towards the intruder. These results suggest that previously demonstrated higher survival of convict cichlid broods in close proximity of mogas may be driven by aggression towards shared enemies. No conclusive evidence was found regarding whether mogas also influence convict cichlids’ investment into anti-intruder aggression: the results show a marginally non-significant trend, and a moderately large effect size, to the direction of a lower investment in mogas’, but not conspecifics’, proximity. More generally, heterospecific neighbours may provide protective benefits in a wider range of ecological settings than commonly considered. Electronic supplementary material The online version of this article (10.1007/s00442-019-04483-0) contains supplementary material, which is available to authorized users.

The elevated plus maze is a prominent and well-documented test for studying anxiety in rodents. Fish are becoming more prevalent in studies of anxiety, yet the elevated plus maze has not been adapted and validated for fish. In the present study, we created an aquatic version of the elevated plus maze called the 'submerged plus maze,' which is shaped like a plus symbol with four arms alternating between black and transparent walls. We used convict cichlid fish (Amatitlania nigrofasciata) and administered diazepam to validate the apparatus for studying anxiety-like behaviour. After diazepam exposure, fish spent more time in and entered more open arms than after vehicle exposure, consistent with the effect of benzodiazepines on rodents in the elevated plus maze. The submerged plus maze maintains construct validity for testing anxiety in convict cichlid fish.

The Convict Cichlid, Amatitlania nigrofasciata, is a popular model organism for behavioral ecologists to study mate choice, monogamy, and parental care. This freshwater Central American fish displays the rare phenotype of reverse sexual dichromatism, and despite the species’ pervasiveness in behavioral laboratories, the role of female ornamentation in this system is uncertain. To better understand the function of female ornamentation, this study characterizes the visual sensitivity of A. nigrofasciata with particular attention to the long wavelength spectral sensitivity needed to perceive female coloration. We find Convict Cichlids to express a trichromatic complement of opsin proteins: SWS2A, SWS2B, and LWS. After confirming the expression of a LWS opsin gene, we inspected the LWS gene in order to speculate on directional selection potentially resulting in heightened sensitivity to female ornamentation. We examined seven tuning residues in the coding sequence of the LWS opsin gene of A. nigrofasciata and...

In September 2007 and May 2014, the Asian fish tapeworm, Bothriocephalus acheilognathi Yamaguti,1934 (Cestoda: Bothriocephalidea), was found in populations of the non-native convict cichlid (Archocentrus nigrofasciatus) and mosquitofish (Gambusia affinis) collected from the discharge channel of a water treatment plant in Los Angeles County. Prevalence and mean intensity of infection of 450 convict cichlids and 70 mosquitofish were 55.3%/9.3 and 11%/1.4, respectively. Overall prevalence and mean intensity of infection in the convict cichlid was higher in 2007 (92%/12.3) than in 2014 (37%/5.4). In 2007, parameters of infection were size-dependent. The highest prevalence/mean intensity of infection was revealed in small fish (100%/15.5) and the lowest in large fish (66.7%/1.5). No statistically significant differences in infection parameters were found in convict cichlids of different size classes in 2014. This paper provides the first documented record of the Asian fish tapeworm infecting a wild po...

Anthropogenic noise can affect behaviour across a wide range of species in both terrestrial and aquatic environments. However, behaviours might not be affected in isolation. Therefore, a more holistic approach investigating how environmental stressors, such as noise pollution, affect different behaviours in concert is necessary. Using tank-based noise exposure experiments, we tested how changes in the acoustic environment affect the behaviour of the cichlid Amatitlania nigrofasciata. We found that exposure to anthropogenic noise affected a couple of behaviours: an increase in sheltering was accompanied by a decrease in foraging. Our results highlight the multiple negative effects of an environmental stressor on an individual’s behaviour.

Defense of a territory is a primary factor determining the fitness of territorial individuals. Thus, territorial animals use a variety of means to lower the cost of territorial defense. Although landmarks are known to lower the defense costs of territories, little is known about how they could affect fundamental properties of territories, which could ultimately affect the demography, population regulation, individual behavior, and spatial ecology of a territorial species. This field study examined the effects of natural landmarks on territory size, shape, and defensive costs in Amatitlania siquia, a little-studied member of the convict cichlid group native to Costa Rica and Nicaragua. We investigated the territorial behavior of 103 breeding pairs in a caldera lake in Nicaragua. During 10-min focal observations, we recorded the locations at which residents chased intruders and then used these locations to outline the territory boundaries. Landmarks affected both size and shape of A. siquia territories. Territory size decreased as the percentage of the boundary at landmarks increased. Territories with

Vertebrate pigmentation is known to be influenced by oxidative stress, but few studies have tested the hypothesis that structural coloration can be similarly affected. We tested whether fish iridophores, which produce structural color using guanine stacks, might be affected by the prooxidant-antioxidant balance of the animal. Specifically, we hypothesized that convict cichlids (Amatitlania nigrofasciata) metabolize guanine present in iridophores to uric acid, an antioxidant, in response to oxidative damage. We used Hunter's contrast gloss and high performance liquid chromatography to determine whether dietary guanine supplementation allows fish to maintain their structural coloration despite oxidative stress induced via ultraviolet-B (UV-B) radiation. We found that dietary guanine was associated with greater skin gloss, and that exposure to UV-B light reduced glossiness. UV-B exposure did not increase oxidative damage (acrolein) or total antioxidant capacity in the skin or liver. Our experiment did not detect effects of dietary guanine or UV-B light on uric acid, but uric acid was positively related to antioxidant capacity. Our results support the hypothesis that structural color in fish may be altered by environmental stressors such as exposure to UV light, and highlight the need for future studies to consider the role of iridophores in condition-dependent visual signaling.

Mobile young under parental care have a high potential for intermixing with other broods, which potentially increases the costs to the foster parents. Here, we examined for the first time the genetic composition of wild-caught broods of the convict cichlid (Amatitlania siquia), a socially monogamous biparental fish, for evidence of brood mixing and adoption. Our microsatellite genotyping data revealed that 79% of broods contained adopted young. Moreover, 25% of broods contained adopted sibsets likely arising from extra-pair matings, a phenomenon hitherto not documented for this species. Overall, adopted foreign fry and host fry in mixed broods were generally different in body length, as would be expected if they have different parents. However, fry from possible extra-pair matings were similar in body length to host fry, suggesting that they are of similar age. Our results are important because they reveal a very high prevalence and degree of brood mixing, and indicate that social monogamy does not necessarily lead to genetic monogamy in the convict cichlid in nature. These findings raise questions about potential brood-mixing mechanisms and the reproductive ecology (especially opportunities for polygamy in nature) of this important model species in the study of animal behaviour.

As part of a revision of the cichlid genus Archocentrus, a new genus, Amatitlania, was erected comprising four species: A. nigrofasciata (the type species), A. siquia, A. kanna, and A. coatepeque. Amatitlania coatepeque is an endemic and an eponym of Lago Coatepeque in the interior highlands of western El Salvador. This species was diagnosed by a Y-shaped pattern formed by the ventral fusion of bars four and five on the body; a triple-spined, squarish, or blunt appearance of the dentigerous arm of the dentary; the presence of a posterior projection at the dorsal corner of the lower lip; the presence of a double medial-loop in the gut; sparsely uniform pigmentation of the peritoneum, and 5–5.5 scale rows from the lateral line to the origin of the dorsal fin. Here we examined the taxonomic status of A. coatepeque using molecular and morphological characters. We found that A. coatepeque is phylogenetically nested within the clade of A. nigrofasciata. Additionally, our re-examination of the reported diagnosti...

Thermally influenced freshwater systems provide suitable conditions for non-native species of tropical and subtropical origin to survive and form proliferating populations beyond their native ranges. In Germany, non-native convict cichlids ( Amatitlania nigrofasciata ) and tilapia ( Oreochromis sp.) have established populations in the Gillbach, a small stream that receives warm water discharge from a local power plant. Here, we report on the discovery of spotted tilapia ( Pelmatolapia mariae ) in the Gillbach, the first record of a reproducing population of this species in Europe. It has been hypothesized that Oreochromis sp. in the Gillbach are descendants of aquaculture escapees and our mtDNA analysis found both O. mossambicus and O. niloticus maternal lineages, which are commonly used for hybrids in aquaculture. Convict cichlids and spotted tilapia were most probably introduced into the Gillbach by aquarium hobbyists. Despite their high invasiveness worldwide, we argue that all three cichlid species are unlikely to spread and persist permanently beyond the thermally influenced range of the Gillbach river system. However, convict cichlids from the Gillbach are known to host both native and non-native fish parasites and thus, non-native cichlids may constitute threats to the native fish fauna. We therefore strongly recommend continuous monitoring of the Gillbach and similar systems.

In the present study, some histochemical features of goblet cells of the intestine of convict cichlid (A. nigrofasciata) were described. In order to reveal the main histological construction, transverse sections of different parts of intestine were firstly stained with hematoxylin eosin (H-E). Sections of anterior, mid and posterior intestinal segments were also treated with different staining methods of alcian blue (AB) at pH 2.5, aldehyde fuchsin (AF), periodic acid-Schiff (PAS), KOH/PAS and PAS/AB (pH 2.5) and investigated. Goblet cells of anterior intestine were colored strongly by AB (pH 2.5), AF and PAS; and moderately by PAS/AB (pH 2.5) (AB dominant). In the mid part of the gastrointestinal tract, goblet cells were also stained strongly with AB, PAS and PAS/AB (pH 2.5) (AB dominant), however, their reactions to KOH/PAS treatment were recorded as negative. Because of numerous supranuclear vacuoles of the epithelial cells, only a few goblet cells could be differentiated in posterior parts of alimentary channel, with their weakly reaction to AB (pH 2.5), PAS and PAS/AB (pH 2.5). Moreover, these cells were not stained with AF and KOH/PAS. According to their affinities, goblet cells oriented in anterior and the mid intestine were mainly classified as acidic (AB-positive) and neutral (PAS-positive). Statistical analysis were confirmed that, the numbers of acidic and neutral cells of per unite square of epithelial area were significantly different.