One of the main aspects of aquatic toxicology is the determination of toxic compounds on organisms that play a significant role in aquatic communities. Cladocerans are suitable as test-objects as they are sensitive for assessing the risk of the presence of pollutants in the aquatic environment. In the methods of biotesting the cladocerans are among the most important groups studied. D. magna is a planktonic freshwater crustacean, commonly found in aquatic ecosystems of Moldova. Its fast maturation, reproductive rate, (with maturity reached at 6–12 days), which make them suitable objects for investigations of productivity of aquatic ecosystems, prevention of intensive phytoplankton growth as well as ecotoxicological studies. Arguments in favor of the use of crustacean D. magna are: high sensitivity, expressivity, ease of maintenance of laboratory cultures, the adequacy of the response to the action of pollutants. Moreover, they are important components of the natural water bodies and their reaction to the action of pollutants under laboratory conditions reflects the influence of these substances on the entire aquatic biocenosis under natural conditions. An important aspect of daphnia cultivation is the content of optimum environmental factors such as temperature, pH of the environment, oxygen content, light, and food resources. Under laboratory conditions D. magna has a lifespan of approximately 50–150 days, the main form of reproduction is by parthenogenesis, but it can also alternate with sexual reproduction, which is an important mechanism for maintaining population fitness. The current investigation aimed at observing if D. magna collected from natural ecosystems can adapt and reproduce successfully under laboratory conditions, to be used in ecotoxicological investigations. The specimens were collected from end of December 2018 from a fish pond in Falesti. The pond was covered with ice, the fish was not active, that allowed an intense development of D. magna and their easy collection for laboratory experiments. The main food source used during laboratory study was Chlorella culture. Two times a week the water was changed, at least 1/4 of water being replaced with new water. The investigations indicated that the species can easily adapt to laboratory conditions. Under normal conditions of light and temperature, D. magna was reproducing asexually, increasing rapidly their population. Under increased temperature conditions or when they were placed in the dark, the sexual reproduction occurred and dormant eggs (ephipia) were produced. Aquarium fish fed on live D. magna were more active in comparison to the dry food. Also a potential was observed in D.magna in preventing of greening of the aquarium due to intense phytoplankton development. Generally, the short term experiments demonstrated that D.magna could be growth successfully in the laboratory for performing short term and long term experiments. Acknowledgements: The study was performed within the projects: 15.817.02.27A, 18.51.07.08A/PS and BSB 027-MONITOX.