Effect of light green and dark brown colored tanks on survival rates and development of tambaqui larvae, Colossoma macropomum (Osteichthyes, Serrasalmidae)

Abstract

The color effect on survival rate and development of tambaqui larvae, Colossoma macropomum, in fish tanks, during a 20 day period, was analyzed. Larvae were fed “ad libitum” and measurements of four limnological variables were conducted daily. Water temperature varied between 24 to 27.8ï‚°C and 24.0 to 27.7ï‚°C in the dark brown and light green colored tanks, respectively. Dissolved oxygen level remained over 6.5 mg/L, pH was alkaline and water conductivity higher than 30 µS/cm. The dark brown treatment displayed significantly (P < 0.05) lower survival rate compared to treatment with light green. Identical effect, however, was not reported with average weight, biomass and larvae total length. Results showed that tank color influences larvae survival rates, where the light green color makes it easier for the larvae to visualize the prey