Osteoporosis is a common bone disease charactereized by deteriorated bone mass and structure. Research on osteoporosis has mainly used mammalian animals as experimental models. Medaka fish (Oryzias latipes) has recently been used for studies on bone and bone diseases because of its excellent experimental characteristics and its remarkable similarity to human in molecular and cellular mechanisms of bone metabolism such as Rankl, a main stimulator for differentiation of bone resorbing osteoclasts. The transgenic medaka rankl:HSE:CFP fish expressing both Rankl and CFP after being heat-shocked was generated in the National University of Singapore. In this fish, induced over-expression of Rankl promotes osteoclastogenesis, leading to bone demineralization and osteoporosis-like phenotypes. This fish line was kindly provided to the laboratory at the Faculty of Biology, VNU University of Science for use as a model for osteoporosis and screening for anti-osteoporosis substances. However, the use of medaka as a model organism has been largely unknown_in Vietnam. Therefore the authors established fish facility and procedures to maintain medaka fish in the laboratory. Moreover, the authors have examined and confirmed that the transgene rankl is genetically and functionally stable in the rankl:HSE:CFP fish after four generations maintained in the facility. This assures the use of the transgenic rankl:HSE:CFP medaka: as a model for osteoporosis for further studies.