Sex reversal, growth, and survival in the guppy Poecilia reticulata (Cyprinodontiformes: Poeciliidae) under laboratory conditions

Abstract

Just like it is important to obtain robust and heavy fish in short periods in aquaculture, in aquariology it is important to efficiently obtain colorful fish, which are usually males, and this makes sex reversal important.  We studied sex reversal and growth for 120 days in 10-gallon tanks, without aeration, with densities of 1 fry per liter. Temperature varied between 28,2 and 28,7°C. The pH was 8,1 to 8,8 and oxygen concentration 6,2 to 6,8mg/l. Aba Api-balanced food with 25% protein was used and three different hormones were added to the treatments: 1) Sten 2) Primoteston and 3) Sostenon 250. Sex reversal in males was 85,0%, 92,5% and 80,0% respectively. Fishes with treatments 1 and 3 gained an average of 0,48g and 4,2cm (with treatment 2: 0,44g and 4cm). Survival was 85%, 92,5% and 80%; however, these differences were not significant. The three treatments gave the expected results of sex reversal, growth and survival.KEY WORDSAnimal feed, population density, hormone supply, aquariums without aeration