Cell cultures are good in vitro model systems in place of using living animals. In the present study, we developed a simple culture method in which tissues were pretreated with a low concentration of sodium hypochlorite solution (NaClO) to prevent not only bacteria but also fungi. Scales removed from a goldfish (Carassius auratus) body were treated with 70% ethanol and then with 0.3% of sodium hypochlorite solution, and cultured in vitro in an atmosphere containing 0.5% CO₂. The doubling time of the established cells (GAKS)^† was 24 hr. The GAKS cells contained alkaline phosphatase activity (8.3±1.1 nmol/min/mg protein) and secreted 0.32±0.07 pg/ml endothelin during a 3 day culture of a full monolayer sheet.