Effect of Stocking Density on Growth, Size Variation, Condition Index and Survival of Discus, Symphysodon aequifasciatus Pellegrin, 1904

Özet

Juveniles of the tropical ornamental fish, Discus (Symphysodon aequifasciatus) of mean standard length, 3.58 ± 0.03 cm and mean weight, 3.36 ± 0.03 g, were reared at four stocking densities (1 juvenile/10 L, 1 juvenile/7.5 L, 1 juvenile/5.0 L and 1 juvenile/2.5 L) with three replicates each, for a period of 12 weeks, to evaluate effect of stocking density on growth, condition index, size variation and survival. Growth and survival were recorded after every two weeks. At the end of the culture period, lower densities of 1 juvenile/10 L and 1 juvenile/7.5 L showed significantly higher growth and survival (p<0.05). The condition index and coefficient of variation did not vary significantly (p>0.05) among the stocking densities but coefficient of variation (CV) increased towards the end of the culture period. Results indicated that discus juveniles may be reared at the highest density of 1 juvenile per 2.5 l up to a period of two weeks without affecting growth parameters significantly, at a density of 1 juvenile per 5.0 l up to a period of six weeks and at a density of 1 juvenile per 7.5 l for a period of twelve weeks. It can, therefore, be concluded that a stocking density of 1 juvenile per 7.5 l is optimal for rearing juveniles of this fish without compromising on specific growth, survival and well-being.