Abstract
The growth, size variability, condition coefficient and percentage of fish with external deformities were compared in juvenile crucian carp (initially 31 mm TL and 0.36 g BW) which were fed intensively four starters only for 120 days at 25°C. The best weight gain was achieved by fish fed an experimental carp diet with the lowest fat content (7.4%) and a commercial diet for eel containing 15.9% fat (4.33 and 4.15 g BW, respectively). In contrast to the experimental diets, both commercial diets produced fish with high condition coefficient values and a very high (37.2 or 62.7%) percentage of individuals with different external deformities. Size variability did increase over the course of the experiment except in the fish fed the high-energy diet for eel. Survival rates ranged between 96.5 and 99.5%. Our results indicate that juvenile crucian carp can be successfully reared exclusively on dry diets but not the commercial ones for eel or carp used in the present experiment.