Abstract: Fishes play important roles in many research fields, such as pollution detection of water, biological accumulation of chemicals in the water and biomedicine. Fishes as laboratory animals have been given close attention by numerous researchers. But the research level is less developed and the standardized fishes strains are scarce. Our country have paid more attention to the research and application of fishes as laboratory animals, and made more efforts on the strains selection and culture. In 1987 the agriculture ministry of China started a program of researching on aquaculture experimental animal. At the beginning of 1990s Institute of hydrobiology of the Chinese Academy of Science researched on Gobiocypris rarus for being developed as a laboratory animal, which next study is focus on gynogenesis, strains select, biological and genetics background. Also Carassius auratus red Vaiety is possibly developed as a laboratory animal. Swordtail ( xiphophorus helleri ) is a kind of small tropical freshwater belonging to the Poeciliidae Family. With the characteristics of small body, omnivorousness, easy breeding, short propagation period, and strong productive capacity, large quantity of individuals can be obtained in a short period, so swordtail is suitable to be use as aquatic laboratory animals. After over decade's research on swordtail, we have achieved the following progress: (1) Breeding of pure strain:5 strains with different body characteristics have been established, among them RR B strain reaches to 22st generation after the problem of “degeneration of close cross" has been overcome. (2) Biological characters:Some of swordtail's characters, such as its outer form, main anatomical structure, habit, growth, propagation, sex reversion, have been comprehended. Histological pictures of its some organs have also been acquired. (3) Nutrition and diet:Artificial formula feed has been used to raise swordtail instead of fishworm, which setting the foundation for setup of nutritional standard and SPF laboratory fish. (4) Water quality:Water self circulate device for swordtail's culture has been installed. (5) Genetics and its detection:The whole sequence of mitochondria cyt b gene, altogether 1140bp, was analysed. Compared with those of other mitochondria DNA in BLAST and GenBank, the results showed there were high homogeneity between swordtail and other fish. Evolved tree established according to the sequences of cyt b gene form swordtail and other 13 kinds of fish, was consistent with traditional classification position. (6) Diseases and their control:Swordtail suffered from more than 10 kinds of diseases. Some diseases are concerned with pathogenies carried by living baits, imbalance of nutrition, worse of water quality, and degeneration of close cross. Routine treatments for disease of fish cultured in ponds had the same effects on swordtail's diseases. Infectious diseases have been controlled in the artificial culture system of swordtail since living baits is substituted by artificial formula feed. Serological techniques were applied in early supervision of bacterial diseases. (7) Application research:Results of toxicity test on disinfectants (sodium dichloro isocynurate,trichlonx isocynuric acid, coalesect iodine, calcium oxide, chloride of lime, potassium permanganate),insecticide (formalin, trichlorfon, malathion) and heavy metal chromium (potassium bichromate) illustrated that swordtail is a representative experimental fish for the security evaluation of aquaculture drugs, and that swordtail has a good foreground in inspection of contamination of some pesticides and heavy metals. Swordtail with different body character, size and sex can be directionally applied. For example, white male swordtail is suitable to be used as the recommend experimental material on toxicology of organic phosphor pesticides. Mortality rate had a significantly gradient change when swordtail was infected with high virulence, middle virulence and weak virulence bacterial strains, and their symptoms were similar to thos

Key words: Swordtail, Laboratory animal

关键词: 剑尾鱼, 实验动物化