Effect of water temperature of culture medium on the sex ratio and survival rate of fighting fish Betta dennisyongi larvae

Abstract

Fighting fish Betta dennisyongi is a popular ornamental freshwater fish in Indonesia. Male fighting fish are preferred because the colour pattern and shape of the fins are more attractive so they are more expensive. This study aims to determine the optimum temperature of rearing media water on the male sex ratio and survival rate of fighting fish larvae. A completely randomized design method with three replications was used in this study. The tested rearing temperature water was: 26°C, 28°C, 30°C, and 32°C. Fish were kept for 40 days. The results of the ANOVA test showed that larval rearing temperature affected significantly the ratio of male and female fish larvae survival (P<0.05). The highest percentage of the male sex was found at a temperature of 32 °C (93.33%), this value was significantly different from other temperature treatments. Meanwhile, the highest larval survival was obtained at a rearing temperature of 28 °C (80.00%), where this value was significantly different from other treatments. Therefore, with economic considerations, it is concluded that the optimal larval rearing media temperature is 28 °C.