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Macropodus opercularis (Linnaeus) (Fig. 111, EAs[SPC]) References. Tan et al., 2013. Distribution. Bukit Brown (Tan et al., 2013). Remarks. This species is sometimes sold as live feed in the ornamental fish trade (Tan HH, pers. obs.)., Published as part of Hui, Tan Heok, Peng, Kelvin Lim Kok, Huan, Liew Jia, Wei, Low Bi, Hing, Rayson Lim Bock, Beng, Jeffrey Kwik Teik & Yeo, Darren C. J., 2020, The non-native freshwater fishes of Singapore: an annotated compilation, pp. 150-195 in Raffles Bulletin of Zoology 68 on page 183, DOI: 10.26107/RBZ-2020-0016, http://zenodo.org/record/5343987, {"references":["Tan JYH, Tan LHC, Quek G, Lim VSF & Tan HH (2013) The fish fauna of Bukit Brown, Singapore. Nature in Singapore, 6: 229 - 237."]}

The round-tailed paradise fish (Macropodus ocellatus) is important to the local ecosystem and economy. Other species in the genus Macropodus are undergoing population declines, indicating that the M. ocellatus population might also be declining. Therefore, the status of M. ocellatus, related to standing-water ecosystem stability and sustainable utilization of fishery resources, requires attention. In this study, we assessed the spatial pattern of the M. ocellatus genetic structure in 10 localities from China. Sequencing of Cytb (1135 bp) and the D-loop (668 bp) yielded 26 and 10 haplotypes, respectively. A total of 30 haplotypes were identified among 165 concatenated mitochondrial DNA sequences. The results showed that the total haplotype diversity of the 10 populations is high (0.910) and that genetic diversity indices for sequences from HuaiAn were the highest (haplotype diversity Hd = 0.780, nucleotide diversity pi = 0.00363). The results of AMOVA indicated that most genetic variation was among populations within groups (80.22%, P

Thanks to its small size, external fertilization and fecundity, over the past four decades, zebrafish (Danio rerio) has become the dominant fish model species in biological and biomedical research. Multiple lines of evidence, however, suggest that the reliance on only a handful of genetic model organisms is problematic, as their unique evolutionary histories makes them less than ideal to study biological questions unrelated to their historically contingent adaptations. Therefore, a need has emerged to develop novel model species, better suited for studying particular problems. The paradise fish (Macropodus opercularis) has a much more complex behavioral repertoire than zebrafish and has been a favored model animal in ethological research during the last decades of the previous century. We believe that with currently available, easily adaptable genetic toolkits, this species could be easily developed into a popular model of behavioral genetics. Despite its earlier popularity, however, the description of a detailed housing and husbandry protocol for this species is still missing from scientific literature. We present here a detailed description of how to raise and breed paradise fish successfully under laboratory conditions, and also discuss some of the challenges we faced while creating a stable breeding population for this species in our facility.

The aggressive behavior of male paradise fish (Macropodus opercularis) was studied. Fish were subjected to three aggressive encounters on consecutive days. If submissive males encountered the same opponent three times, the last aggressive encounter was very different than the first one. When the animals faced a new opponent each day, the changes were much less pronounced. We conclude that (1) fish are able to recognize their opponents at least one day after the encounter ("social recognition"), and (2) social recognition modifies the effect of prior defeat ("status-related memory") in subsequent encounters.

Aquarium trade has been the source of many alien species being introduced into the natural waters of Chennai. Trichopsis vittata and Macropodus opercularis are being reported for the first from Chennai. However, contrary to the propagule pressure theory both these species are not common in the aquarium trade, raising speculations of inter-basin water transfer playing a role in introducing non-native species into an ecosystem.

We report on mycobacteriosis in an imported tropical ornamental fish Macropodus opercularis commonly known as the paradise fish. Mass mortality occurred in paradise fish imported to Korea from Southeast Asia in 2008. The affected fish did not show any outward clinical signs, but enlargement of the spleen, kidneys, and liver was observed on dissection. Histopathological examination revealed numerous granulomas in the spleen, and acid-fast bacilli were observed in the centers of the granulomas. About 65% of spleen DNA samples were PCR positive using mycobacteria-specific primers targeting the 16S rRNA and hsp65 genes. The nucleotide identities of the 16S rRNA and hsp65 genes with those of Mycobacterium marinum were 99.5% and 99.4%, respectively. Although the bacterium was not cultured, the molecular diagnosis and histopathological findings were consistent with mycobacteriosis in paradise fish.

The characteristic of fish fauna and population Zacco koreanus was investigation in the Bongseonsa Stream Gyeonggi-do, Korea from May to September 2011. The collected species during the survey period were 22 species belonging to 9 families. Among them, one species (Cottus koreanus) was classified as an endangered species in Korea. Ten species (45.5%) were endemic species of Korea. Dominant species was Rhynchocypris oxycephalus (St. 1), Zacco platypus (St. 2, 4, 5, 7), Z. koreanus (St. 3), and Squalidus gracilis majimae (St. 6). When our data were compared with the previous data (1932, 31 species) and this date (23 spcies), Anguilla japonica, Acheilognathus signifer, Hemibarbus labeo, Hemibarbus mylodon, Gnathopogon strigatus, Saurogobio dabryi, psariichthys uncirostris amurensis, Lefua costata, Pseudobagrus fulvidraco, Pseudobagrus koreanus, Oryzias sinensis, Trachidermus fasciatus, Coreoperca herzi, Siniperca scherzeri, Micropterus salmoides, Macropodus chinensis and Channa argus 17 species were not sampled, but Pseudorasbora parva, Microphysogobio yaluensis, Orthrias nudus, Silurus microdorsalis, Odontobutis platycephala, Odontobutis interrupta and Micropterus salmoides 7 species could new taxa fiend its existence at the Bongseonsa Stream. Length-weight relation in the population of Z. koreanus was BW=0.0000007TL3.03, and condition factor in the population was average 0.78. Frequency analysis of total length indicated that the group 40∼80 mm in total length is represented by one-year-old individuals, the group 90∼120 mm by two-year-old individuals, and the group over 130 mm by three-year-old individuals. This species was stabilized spawn in the Bongseonsa Stream since then introduction, 2007.

In this study, the complete mitochondrial genome of Macropodus opercularis was sequenced using Illumina-based de novo transcriptome technology and annotated using bioinformatic tools. The circular mitochondrial genome was 16,496 bp in length and contained two ribosomal RNAs, 13 protein-coding genes, 22 transfer RNA genes, and the control region. The gene composition and order were similar to suborder Anabantoidei. Phylogenetic analyses using concatenated amino acid and nucleotide sequences of the 13 protein-coding genes with two different methods (Neighbor-joining and Bayesian analysis) both highly supported the close relationship of M. opercularis to M. ocellatus , consistent with previous classifications based on morphological and molecular studies. Furthermore, family Channidae and Parachanna insignis were clustered in the same clade. Our results supported the inclusion of family Channidae in suborder Channoidei. The complete mitochondrial genome of M. opercularis will provide genetic markers for better understanding species identification, population genetics and phylogeographics of freshwater fishes.

Paradise fish exhibit complex, environment-specific behavioral responses which consist of behavioral elements (motor and posture patterns) appearing in a typical, correlated manner. The genetic and environmental components underlying these phenotypical correlations have not been comprehensively investigated. Therefore, we have analyzed the behavioral elements of paradise fish from the nine populations of a 3 x 3 full diallel cross by employing a bivariate extension of the Hayman-Jinks variance-covariance analysis, demonstrating the presence of significant environmental and genetic correlations. To investigate the multivariate structure of the correlation matrices obtained, we subjected the phenotypical, environmental, additive genetic, and dominance correlations to principal-component analyses (PCAs). After rotation, the phenotypical principal factor pattern found was similar to previously obtained ones, suggesting stable underlying biological mechanisms. The environmental PCA extracted several environmental principal factors that were highly situation-specific. PCAs of the matrices of genetic correlations extracted only a small number of genetic principal factors which were not situation-specific, suggesting a relatively simple underlying genetic structure.

In Taiwan, a fish conservation farm had about 6,250 Taiwan paradise fishes, Macropodus opercularis (L.), which were separately cultivated in an outdoor tank containing 3,250 fishes, and an indoor tank containing the rest. The water supplying both tanks was the same running water source from the adjacent hills. Following a change in the fish feed (the commercial aquaculture feed became eel’s feed) to all fishes in May 2010, rotten body surfaces were only found in diseased and dead fishes in the outdoor tank. Interestingly, no sick fishes were found in the indoor tank. The clinical findings of the diseased fishes were bleeding at basal fins, peripheral site of genital pore, and bilateral surface of the abdomen. Additionally, we discovered whitish-mucus gills, edema of the intestines, and multi-focal white tubercles in infected fishes during gross examination. The results of the histopathology study showed that there were numerous multi-focal granulomas in the spleen, posterior kidney, and liver. Furthermore, Photobacterium damselae subsp. piscicida was isolated from lesions of the ailing fishes. We conducted an experimental animal virulence test, and our data revealed that P. damselae subsp.piscicida was a highly virulent pathogen. Fortunately, P. damselae subsp. piscicidaappeared to be susceptible to most commonly used antimicrobial agents, according to the results of the antibiotic sensitivity study. We recommended a treatment with oxolinic acid (20 mg/kg/day) in the feed for 7 days for all Taiwan paradise fishes. The fishes’ condition significantly improved and the disease appeared to be controlled. Key words: Conservation, photobacteriosis, Taiwan paradise fish, virulence.

297. Trimmatom macropodus Winterbottom, 1989:2404, figs.1–2 Paratype: USNM 293529 (13.0), 21°57’48”N, 121°13’32”E, [in error, 21°55’15”N, 120°49’45”E,] south end of rocky shore just south of Chin –chiao–wan, 0–6 m, 8 May 1968, coll. V. G. Springer and J. Choat. Other type: AMS I. 19456–113 (holotype) and 2 paratypes (1, c & s)., Published as part of Ho, Hsuan-Ching & Shao, Kwang-Tsao, 2011, 2957, pp. 1-74 in Zootaxa 2957 on page 59, {"references":["Winterbottom, R. (1989) A revision of the Trimmatom nanus species complex (Pisces, Gobiidae), with descriptions of three new species and redefinition of Trimmatom. Canadian Journal of Zoology, 67, 2403 - 2410."]}

Megalocytivirus was detected from paradise fish Macropodus opercularis imported from Indonesia. Four of 11 fish (36%) in 2006 and 40 of 117 fish (34%) in 2008 were found to be PCR- positive for megalocytivirus. Phylogenetic analysis based on partial major capsid protein (MCP) gene nucleotide sequences revealed that the sequences detected in paradise fish were classified as Geno- type II, which includes freshwater fish isolates from Southeast Asian countries, closely related to infectious spleen and kidney necrosis virus (ISKNV), Murray cod iridovirus (MCIV), and dwarf gourami iridovirus (DGIV-2004). Paradise fish was added as a new host for megalocytivirus based on this study.

Two fish species, Astronotus ocellatus (Cichlidae) and Macropodus opercularis (Anabatidae) were tested for predacious behavior toward immature mosquitoes (Aedes fluviatilis, Diptera:Culicidae) and schistosomiasis snail hosts (Biomphalaria glabrata, Mollusca:Planorbidae), in the presence or absence of non-living food and in laboratory conditions. A. ocellatus, a species indigenous to Brazil, was a very efficient predator of both organisms (alpha = 0.05); M. opercularis, an exotic species, preyed well on immature mosquitoes, but small snails and snail egg-masses were ingested only irregularly. Both fish species seemed to prefer live to non-living food.

Species-specific elements of the paradise fish's ethogram were recorded in one familiar and three different unfamiliar environments, which were designed to model certain features of this species' natural habitat: (1) a densely vegetated home range, (2) a novel open field, (3) a small novel place, and (4) a small novel place with a predator. The inheritance of the behavioral elements was investigated employing a five-times-replicated diallel cross among three inbred strains. A detailed Hayman analysis of variance and a variance-covariance analysis were performed to uncover the genetic architectures of these phenotypes. Additive genetic effects and/or ambidirectional dominance was found to be characteristic of most species-specific behavioral elements studied, suggesting an evolutionary history of stabilizing selection.

In this paper, the quantitative post-embryonic development of the Asian freshwater fish nematode Camallanus cotti Fujita, 1927, is described. Larval and adult morphometrics were obtained by following the parasite's life cycle experimentally using copepods Macrocyclops albidus (Jurine) as intermediate host and guppies Poecilia reticulata (Peters), southern platyfish Xiphophorus maculatus (Gunther) and paradise fish Macropodus opercularis (L.) as definitive host. Additionally, adult worms were obtained from heavily infected paradise fish imported from Singapore. It is suggested that the gradual change in proportions of the worm's somatic body parts reflects the specific ecological role of each developmental stage. The free-living infective first- stage larva seems to be adapted for transmission, as indicated by its relatively long tail, designed to generate host-attracting movements, and its non-functional intestine. The second- and third-stage larvae from the copepod intermediate host seem mainly to invest in trophic functionality, i.e., the development of the buccal capsule and the oesophagus, which are crucial structures for the worm's successful establishment in the definitive fish host. Once in the fish intestine, the larvae enter a period of considerable growth. After the fourth (i.e., last) moult, a 72% increase in average female body length occurs. This is accompanied by doubling the average vulva-tail tip distance and the average tail length. The length of the female hind body expands in an accelerating allometric fashion, and seems to be closely linked to the posterior-wards expansion of the uterus. In the males however, growth seems to cease after the final moult. We conclude that female post-maturational body size, but especially the length of the hind body and the tail, are closely related to reproductive state, i.e., the developmental stage of the offspring in the uterus, and, probably, the worms' age. Any future taxonomical studies of camallanids in general, and C. cotti in particular, should thus be aware of the reproductive state of the females used.

In the rutaceous subtribe Cuspariinae, species with relatively large, valvate, colored calyces have been assigned to Erythrochiton, but differences in arrangement of leaves, type of inflorescence, union of petals, of filaments, and of carpels, indument of corolla and testa, appendages of anthers, height of the intrastaminal disc, and exine of the pollen argue for the recognition of three genera. Erythrochiton s. str., characterized by often perennating inflorescences, connate, usually glabrous petals, free carpels, tomentulose seeds, and spinulose exine, consists of seven species of which four are new: E. fallax from the eastern flanks of the Andes from Colombia to Bolivia, E. odontoglossus from western Ecuador and adjacent Peru, E. trichanthus from eastern Peru, and E. gymnanthus from Costa Rica. The assignment to Toxosiphon of four species with woolly, coherent petals, connate carpels, glabrous seeds, and reticulate exine necessitates three new combinations: T. carinatus, T. macropodus, and T. trifoliatus. Recognition of a third unispecific genus with opposite simple leaves, sparsely pubescent, coherent, clawed petals, and spinulose exine requires a new genus name, Desmotes, and a new combination, D. incomparabilis.

Maximum Reactive Distance (RDmax) and the area of the Reactive Perceptual Field (RPF) for the fish Macropodus cupanus were determined, using the fourth instar mosquito larva (Culex fatigans) as the prey organism. RDmax and the area of RPF increased with increasing body weight of the fish as well as increasing food deprivation time. Satiation time (St) as a function of the weight of the fish and aquarium temperature were also determined. In larger W classes (570 and 270 mg) St was not influenced by temperature. To get satiated the smallest W class (80 mg) required feeding periods of 40, 30 and 20 minutes at 22 or 27, 32 and 37°C, respectively.

Fish 20–100 days of age were observed in brief conflicts with a stimulus fish of similar size and age. Four stages of behavior development were identified, based on quantitative changes in behavior which occurred with increasing age. Relatively little aggressive behavior occurs in the larval stage which includes fish up to about 40 days of age. Juveniles, age 40–70 days, approach, chase, and attack each other much more than do the larva. In the adolescent stage, 70–100 days of age, the incidence of species typical displays increases paralleling the onset of puberal changes in the testis and ovary. No sex differences in behavior were seen in fish up to 100 days of age. Among adult fish of unknown age males performed lateral threat displays more frequently than females as has been previously reported.

Surfacing frequency (Sf) in obligatory air-breathing fishes is a behavioural index of O2 uptake; as both are interrelated, there is a possibility of predicting one from the other. From the point of cause and effect relationship, feeding (C) is regarded as the cause and Sf and O2 uptake as its effects. Hence, the last two are predictable from the cause. A pathway for predicting the bioenergetics components, feeding (C), metabolism (M) and growth (P) from a behavioural index of surfacing frequency has been proposed. In this model, C occupies the focal point connecting on the horizontal plane Sf on one side and P on the other side and M vertically. The developed multiple regression models predict the bioenergetics components of the fishes,Macropodus cupanus andChanna striatus of different weight classes ex-posed to different rations and temperatures; the percentage of variation accounted for by the equations is over 90. The pathway can also be followed for predicting bioenergetics components of gill-breathing fishes, if feeding rate alone is known. On application of the relevant part of the pathway toSalmo trutta, the percentage of variation accounted by the equations is 95.

Previous experiments in several teleost species suggested that defensive reactions are increased following extensive bilateral ablation of the telencephalon. We investigated the effects of varied telencephalic lesions on the reaction of fish to handling and placement in an unfamiliar tank. When intact or sham-operated males were handled, they showed increased rates of surfacing for air. Males which were previously administered bilateral (TLX) or unilateral (UTLX) telencephalon ablation suppressed activity following handling. TLX lesions resulted in the greatest suppression reactions; in addition, the TLX males showed slightly decreased rates of activity prior to handling. Extensive, bilateral lesions of the dorsal telencephalon did not induce the suppression reaction in most males. Based on the results, we propose that one of the functions of the teleost telencephalon is to modulate defensive behavior. The structures which influence defensive behavior appear to be located in the ventral and possibly the rostrodorsal area of the telencephalon.

Behavior during 5-day spawning trials of intact, sham-operated, olfactory bulb-ablated, and telencephalon-ablated male paradise fish, Macropodus opercularis, was investigated. Spawning and nestbuilding were eliminated in the telencephalon-ablated males and unimpaired in the sham-operated and olfactory bulb-ablated individuals. Telencephalon ablation resulted in decreased frequencies of frontal display, attack, and bubble blowing and differences in the probability of certain behavior sequences. The data indicate that the block of reproduction is a result of interference with nonolfactory functions of the telencephalon. Telencephalon ablation was previously reported to block spawning and foamnest building in male Macropodus opercularis (Davis et al., 1976). Lesioned males paired individually with intact females showed decreased frequencies of social behaviors at the start of the spawning trial, and during the trial they were subordinate to the female. The present study was undertaken to investigate in greater detail the effects of telencephalon ablation on reproductive behavior. The telencephalon ablation resulted in the destruction of the olfactory system. Olfactory stimuli strongly influence social behavior in fishes (Atema et al., 1969), including Macropodus (Rossi, 1969; Davis and Pilotte, 1975). The loss of olfaction rather than of nonolfactory functions of the telencephalon may be responsible for the block of reproduction. To examine this possibility we investigated the effects of olfactory bulb ablation on sociosexual behavior.

Socially isolated Macropodus opercularis showed a distinct approach response to water taken from the tank of a conspecific individual or a nonconspecific, Trichogaster trichopterus, but not to water from a tank without fish. It is proposed that these species produce chemical stimuli which are attractive to M. opercularis. Approach frequency and the total duration of approach during a 10-rain period of stimulation varied with the species and the sex of the stimulus fish but not with the sex of the subject. Subjects responded most frequently to the conspecific male and nonconspecific female stimuli and, least to the nonconspecific male stimuli. Rossi (1969) reported that solitary male Macropodus opercularis (family, Belontiidae; subfamily, Macropodinae) show increased nest building and aggressivity in response to female chemical stimuli. Observations in this laboratory during various experiments on social behavior (Davis, Harris, and Shelby, 1974) confirm that mature 34. opercularis respond to chemical cues from species mates. Water that has contained a female for a period of days can elicit immediate arousal consisting of erection of the medial fins and striking changes in skin color in an isolated male. These are elements of the species-typical responses which are seen in courtship and nest defense (Forselius, 1957; Ward, 1967). In addition, in a situation in which female stimulus water is" added slowly through a tube at the water surface, fish approach the incurrent tube and investigate the opening. The approach response occurs even when the behavioral arousal response does not, as when the stimulus is diluted with fresh water prior to entering the tank. 1We thank Jessie Shelby for her valuable technical assistance. 2Liem's classification of the order Anabantoidei into four families is preferred because it presents a more convincing hypothesis of the natural relationships between the divergent species in this group than does the older classification of Regan (1906).

The possible role of eyespot patterns in predator recognition by paradise fish was examined using a passive avoidance conditioning technique with various dummies or live goldfish. It was found that a low-intensity shock, although clearly uncomfortable, elicited exploratory behavior in the fish and that observable learning did not occur. However, if the paradise fish was shocked in the presence of a live goldfish or various fish dummies, exploration diminished and avoidance learning was detected. This was characterized by a considerable increase in latency to enter the shocked compartment. The most effective dummies were those with two laterally arranged eye-like spots. The possible role of species-specific key stimuli in avoidance learning and organizing defensive behavior of the paradise fish is discussed.

Sex steroid concentrating cells in brain can be demonstrated by the specialized technique of steroid autoradiography. With this technique we have demonstrated the presence and the pattern of sex steroid concentrating cells in a representative species from every major class of vertebrate. This paper discusses the details of the pattern of binding cells found in a teleost, the paradise fish, Macropodus opercularis ; a reptile, the lizard, Anolis carolinemis ; and a carnivore, the mink, Mustela vison . The majority of sex steroid concentrating cells are found in the medial preoptic area, the medial hypothalamus, limbic structures and specific areas of the mesencephalon deep to the tectum. The regions containing the largest numbers of labelled cells have been demonstrated in each species with other techniques to be involved in neuroendocrine regulation or control of sex behavior.

Transversotrema chackai sp. nov. adult of Cercaria chackai, is described. They are found as adults beneath the scales of three species of fishes, Macropodus cupanus (CUV & VAL), M. cupanus var. Dayi (DAY) and Barbus puntius (HAM & BUCH). This species is compared with other known adults of the genus Transversotrema and the creation of a new species is justified.

Pretrial intramuscular administration of the antigonadotropin, methallibure suppressed operant responding for conspecific visual stimulation. Four administrations of the drug during an 11 day period did not noticeably impair gametogenesis. Oral administration of methallibure for 5 weeks resulted in a decrease in frequency of lateral display, but not frontal display, in a 10 min trial with a live stimulus male, and a decrease in the gonadosomatic index and fertility but not spawning readiness. The possibility that methallibure disrupts catecholamine synthesis is discussed.

The effects of prior dominance experience on agonistic behavior were investigated in male paradise fish, Macropodus opercularis, with particular reference to the social conditioning hypothesis. The subjects had only limited social experience prior to the pre-test treatments; their pre-test dominance histories were controlled experimentally, through rigged contests (based on relative size). Following the pre-test conditioning treatments, the treated fish were paired with naive siblings of the same standard length, and subjected to a battery of four tests: two measures of aggressiveness, one of reactivity and one of social dominance. The latter consisted of a dyadic encounter with a naive sibling in a neutral aquarium. Four separate experiments were conducted, each exploring a different parameter of social dominance. It was found that negative dominance experience resulted in a significant decrement in subsequent dominance success and in increased reactivity levels, but had no influence on the measures of aggressiveness. Positive dominance experience had no effect on any of the response measures. The implications of the asymmetry in the effects of dominance experience (particularly with regard to subsequent dominance scores) for the social conditioning hypothesis and the associationist paradigm in general, as it applies to agonistic behavior, were explored. It was concluded that the social conditioning hypothesis cannot account for the results obtained here or for those of related studies. The relationships between the measures of aggressiveness and the measure of social dominance were also discussed.

The readiness to perform species typical social displays and the readiness to startle in reaction to novel stimuli are increased in socially isolated paradise fish. Males that are kept in large, bisexual populations or have been socially isolated for a few hours show low display and low startle readiness. Reactivity is increased following 1 day of social isolation, and a further increase is obtained by prolonging the isolation up to 4 days. Males that receive continuous visual stimulation from a conspecific male or from a goldfish for 4 days show reduced display and reduced startle readiness. Social isolation appears to have general effects on behavior, increasing reactivity to various kinds of stimuli in addition to social stimuli. It is proposed that isolation-induced increases in display readiness are largely a result of the low level of external stimulation. Social isolation may or may not have specific effects on social display readiness.

Tritiakd estradiol or testosterone was administered to gonadectomized male paradise fish, Macropodus opercularis, to investigate the neuroanatomical location of sex steroidretaining cells. Each male was sacrificed 2 hr following intraperitoneal injection of the labeled hormone. Autoradiograms were prepared, and sections were taken from the entire brain, the anterior spinal cord, and the pituitary. Following 4 to 12 months of exposure, the distribution of labeled cells was seen to be the same for males which had received the estradiol as those which received testosterone, but estradiol resulted in a greater number of labeled cells. Steroid-concentrating cells were located in the ventral telencephalon, preoptic area, lateral tuberal nucleus, nucleus of the lateral recess of the third ventricle, and caudal portion of the posterior periventricular nucleus. In addition, the

Passive dark avoidance conditioning was studied in four inbred strains of paradise fish in the presence and absence of a fish-like dummy during the training process. Strain differences were found in exploratory activity during habituation trials and also in the sensitivity to the mild electric shock punishment. The impact of the fish-like dummy also depended on the genotype.

1. The normal paradise fish adapts itself by appropriate color changes to environments of black, white, red, yellow, and blue.2. Analogous but less adaptive changes occur in the albino.3. The reactions of melanophores, xanthophores and erythrophores which produce these color changes are described.4. Dark caudal bands, formed by cutting chromatophore nerves in the caudal fin of normal paradise fish fade in approximately ten hours. Similar bands in the albino fish fade in about four hours.5. The evidence indicates the presence of independent dispersing neurohumors for melanophores and for erythrophores.6. The rate of caudal band disappearance is directly proportional to the temperature, and a rise of about ten degrees in temperature very nearly doubles this rate.

1. In the paradise fish, Macropodus opercularis, the dark-colored or normal type is a Mendelian dominant to the albino.2. A description is given of the cell groupings which form the basis of the color pattern.3. The melanophores are entirely absent from the albino but all other types of chromatophores are present.

Betta splendens (Siamese fighting fish) were given 10 days of visual preexposure to either Macropodus opercularis (paradise fish) or their own mirror images. Separate groups of bettas were then allowed to display aggressively toward one of the following stimuli: a conspecific, an alien species (Macropodus opercularis), or a mirror image. Bettas displayed more frequently, and for a longer duration, when tested with either another betta or their own image than when tested with a macropodus. Bettas required more time to reach a criterion of no displays when tested with their own mirror image than when tested with the macropodus fish; this measure did not differ between the betta test condition and the macropodus test condition. Strength of aggressive displays in bettas is dependent of previous exposure conditions (Miley & Burack, 1977), the particular stimuli used in behavioral testing, and measures used in recording the aggressive response.

Laboratory experiments on repro duction and embryological development traditionally use frogs or toads (Ben-Gal 1974). We suggest the use of the blue gourami, Trichogaster trichopterus (Pisces, Belontiidae) as an alternative subject in such experiments. The blue gourami is a member of a family of tropical fishes (Belontiidae) with many well-known representatives, including the Siamese fighting fish (Betta splendens), the paradise fish (Macropodus opercularis), and the dwarf gourami (Colisa lalia). Because it is an air breathing-fish native to the stagnant rice paddies and temporary swamps of South East Asia, no aeration equipment is required. Blue gouramis are easily bred in the laboratory, and they provide thousands of eggs throughout the year. Breeding need not be induced by the administration of exogenous hormones as with most amphibian preparations. The numerous advantages of using blue gourami eggs for embryological demonstrations include the following

The effects of castration on male spawning behavior, nestbuilding and fertility were measured in a five day spawning trial with an intact female. Spawning and fertility decreased one week following castration while nestbuilding was unaffected. Sham operated males showed normal spawning and fertility. Two weeks postoperatively, fertility and spawning were increased paralleling partial regeneration of the testes. The antigonadotropin methallibure blocked testes regeneration and recovery of spawning in castrated males but it had no effect on reproductive functions of intact males. Spawning did not decrease in one-week castrated males which were administered testosterone enathanate. The results suggest that gonadal androgen facilitates sexual behavior in Macropodus.

Macropodus opercularis were reared in isolation, with conspecifics, or cross-reared with nonconspecifics. As young adults, cross-reared subjects presented with live conspecific and mirror image stimuli performed social displays less frequently than controls, while isolates did not differ from controls. In a spawning trial, no differences were found between groups. These results suggest that experience with an alien species may reduce the readiness to perform species-specific social displays. Investigations of imprinting and attachment behavior indicate that social stimulation is necessary for the ontogeny of species-typical social behavior in mammals (Cairns, 1972) and in birds (Bateson, 1966, 1971). Juvenile mice, sheep, and dogs which have previously been kept with members of an alien species may show attachment behavior toward the nonconspecific (Denenberg, Hudgens, and Zarrow, 1964; Nagy, 1965; Cairns and Johnson, 1965; Cairns and Werboff, 1967; Fox, 1969). The effect of cross-species rearing on adults social behavior has apparently not been extensively investigated. As adults, Mus reared with Baiomys show a social preference for Baimoys, though the Mus freely mate with conspecifics (Quadagno and Banks, 1970). Lagerspetz and Heino (1970) found that mice cross-reared with rats preferred rats in a social preference test as adults, and showed reduced sexual behavior toward mice. Adult male guinea pigs which are reared with chickens or rats court conspecifics and the cross-reared species as well (Beauchamp and Hess, 1971, 1973). Social isolation beginning early in development has marked effects on adult behavior. Rats isolated as early as 14 days show normal sexual behavior (Beach, 1958), although neonatal isolation disrupts adult mating behavior (Gruendel and Arnold, 1969). Isolated male guinea pigs, cats, and dogs exhibit poorly organized sexual behavior patterns (Valenstein, Riss, and Young, 1955; Rosenblatt, 1965; Beach, 1968; Coulon, 1971) and isolation-reared rhesus monkeys show profound disruption of adult social behavior (Harlow and Harlow, 1966). In some birds the development of a juvenile social attachment 343

The aggressivity of adult males and females was evaluated by measuring (1) the frequency of aggressive displays that individuals made toward a mirror image stimulus following varying periods of social isolation, (2) the display frequency in brief, unisexual and bisexual bouts with live opponents, and (3) the reinforcing effects of mirror image stimulation on performance of an approach response. Isolation up to seven days increased aggressivity in both sexes. Males performed lateral display toward a mirror image or a live conspecific more frequently than females. Mirror image stimulation also was a stronger positive reinforcer in males than in females.

Bilateral ablation of the telecephalon at the level of the anterior commissure blocked reproduction in male paradise fish. Lesioned males performed species typical displays at the start of the spawning trial but thereafter avoided the female, and they did not build nests. All the sham-operated males spawned and built nests. The reaction of the male to a startle stimulus and the rate of operant responding for visual reinforcement were used as additional, independent measures of the behavioral effects of the ablation. Removal of the telencephalon greatly increased startle reactivity and decreased the rate of operant responding. Hyperreactivity could account for long response latencies, reduced mobility, and other reported effects of telencephalic ablation in teleosts which have previously been attributed to impaired nonspecific arousal.

Behavioral responses to novelty of female paradise fish were investigated. Individuals of four pure-breeding strains and an outbred population were compared in a variety of standard behavioral tests. An ethological description of the same subjects was obtained by recording time sequences of defined behavior elements. Results on standard psychological tests were related to ethologically defined behavioral units by factor analysis.

Ablation of the telencephalic hemispheres blocked reproductive behavior and decreased the rate of operant responding for conspecific visual reinforcement. Repeated administration of operant conditioning sessions for 4 weeks following the ablation resulted in a partial recovery of the operant rate but not of reproductive behavior. Social isolation, which increases reactivity in Macropodus, had no significant effect on the operant rate in sham-operated or lesioned males. Lesioning resulted in a significant reduction of testes weight and the gonadosomatic index in 8 weeks.

Previous investigations in male Macropodus showed that simultaneous bilateral removal of the telencephalon results in decreased sexual and nest-building behavior. The current investigation was to determine whether serial unilateral ablation of the telencephalic hemispheres, increased recovery time following simultaneous ablation, or prior spawning experience can produce savings in reproductive behavior. Preoperative sexual experience did not alter the behavioral effects of telencephalon ablation. All components of reproductive behavior were decreased following serial or simultaneous ablation of the telencephalon, but none were eliminated. When simultaneous ablation males were allowed to recover for a period of time equal to that following the second operation of the serial ablation, they showed less sexual behavior than the serial ablation males. When the recovery time was equal to that following the first operation of the serial ablation, the simultaneous and serial ablation males showed no significant differences in reproductive behavior. The results indicate that removal of one lobe of the telencephalon initiates alterations in nontelencephalic structures which result in increased savings in sexual behavior following removal of the second hemisphere. Similar neural alterations may be responsible for the recovery of function following simultaneous bilateral ablation of the telencephalon.