GROWTH PERFORMANCE OF ANGELFISH, PTEROPHYLLUM SCALARE (SCHULTZE, 1823) FRY REARED AT DIFFERENT STOCKING DENSITIES WITH UNDER-GRAVEL FILTRATION SYSTEM-

摘要

The study was conducted to evaluate the effect of different stocking densities on the growth and survival of ingelfish, Pterophyllum scalare fry reared in all-glass tanks with under-gravel filtration system. In the experiment, angelfish fry with length and weight in the range of of 1.3-1.6 cm and 0.060-0.076 g were reared at different densities, Le. 3 fry L', 2 fry I/1,1 fry L1 and 0.5 fry L1 for a period of 45 days in all glass tanks (36 L) with undergra vel filtration system. The experiment ro conducted according to completely randomized design with four replicates for each density. The freshwater was added to compensate evaporative water loss from the tanks, but no water exchange was carried out in the experimental tanks. Fry were fed flake feedcontaining 49.02% crude protein. The fry reared at the density of 0.5 fry L*' showed significantly (P<0.05) higher length gain (153.6593%), weight gain (967.5915%) and specific growth rate (5,2622%) than that of fry reared at other densities. The densities of 0.5 and 0.1 fry I/' resulted in 100% survival which was found significantly better (POM) than that of fry reared at densities of 2 and 3 fry L1. Decreased growth was observed with increase in stocking density. However, due to use of under gravel filtration system water quality parameters were found to be in optimal range for certain period at different stocking densities. Hence, water quality and consequently fish production of angel fish fry in aquaria can be optimized with the stocking density of 0.5 and 0.1 fry L1 with use of under gravel filtration system.