Larval feeding behavior of angel fish Pterophyllum scalare (Cichlidae) fed copepod Eucyclops serrulatus and cladoceran Ceriodaphnia quadrangula

Three different live diets, Eucyclops serrulatus, Ceriodaphnia quadrangula and equal combination of E. serrulatus copepodid and C. quadrangula, were offered to angelfish (Pterophyllum scalare) larvae viz 1-week, 2-week and 3-week old at prey densities of 2, 5 and 10 individuals mL⁻¹. Results showed that 1-week-old P. scalare larvae consumed E. serrulatus copepodid at a rate of 31.3–56.7 ind. h⁻¹, C. quadrangula at 8.0–12.0 ind. h⁻¹, and mixture of E. serrulatus and C. quadrangula at 20.7–40.7 ind. h⁻¹. For 2-week- and 3-week-old larvae, consumption rate increased accordingly. The electivity indices (E) of P. scalare (1-week-old larvae) for E. serrulatus copepodid were +0.18, +0.23 and +0.22 at prey densities of 2, 5 and 10 ind. mL⁻¹ respectively. Tendency towards E. serrulatus copepodid consumption reduced by aging P. scalare as indicated by the E values for 2- and 3-week-old larvae. However, growth and survival of P. scalare larvae was greatest when fed on combination of copepod E. serrulatus and C. quadrangula.