Potential Feed Conversion of Redear Sunfish Fed Nutritionally Complete Formulated Diets

Intensive culture of redear sunfish Lepomis microlophus has been difficult because these fish do not readily accept formulated diets. Many fish culturists have continued to raise redear sunfish in ponds on formulated diets, but it is uncertain whether the fish are effectively using the provided feed or the feed is simply adding nutrients to the pond. We examined the feed conversion, relative condition, and body composition of redear sunfish fingerlings fed three nutritionally complete commercial formulated diets in recirculating-water, biofiltered aquaculture systems. Redear sunfish accepted all three diets after an initial training period of 3 weeks. Increases in total length and weight were noted for all three diets; however, condition factors only increased for fish fed two of the diets. Proximate body composition appeared to be related to composition and particle size of the diets. Feed conversion ratios for fish fed one of the diets were similar to those reported for hybrid sunfish (bluegill L. macrochirus × green sunfish L. cyanellus). Redear sunfish feed conversion ratios were higher than those reported for channel catfish Ictalurus punctatus or Mozambique tilapia Oreochromis mossambicus but were similar to those for rainbow trout Oncorhynchus mykiss and common carp Cyprinus carpio.