Effect of diet and light regime on growth and survival of African catfish (Clarias gariepinus) larvae and early juveniles

Growth of larval sharptooth catfish Clarias gariepinus fed live Artemia nauplii , a specially prepared dry feed (MN-3), a commercial dry salmon starter feed (Silver Cup 3600), or a combination of 50% live Artemia and 50% MN-3, under conditions of either light or dark for 21 days was studied. For all diets, fish reared in darkened tanks were significantly larger than those in illuminated tanks from day 8 onwards. Fish fed a combination of live Artemia plus MN-3 grew significantly more quickly than those fed either live Artemia or MN-3 only. On day 21 of the experiment, average weight of fish fed the combined diet was 649 ± 30 mg (mean ± SEM ) in darkened tanks and 445 ± 16 mg in illuminated tanks, while those fed Artemia alone were 242 ± 9 and 198 ± 13 mg (dark and light, respectively) and fish fed MN-3 only were intermediate at 377 ± 20 and 267 ± 16 mg (dark and light, respectively). Catfish fed the salmon starter initially grew slowly, but after day 11 grew more quickly than the other groups. Mortalities were highest for fish fed salmon feed.
Permanent darkness enhances the growth of C. gariepinus larvae during and after metamorphosis. While dry diets promoted higher growth rate than live Artemia nauplii alone, a combination of the two resulted in the fastest growth.