Comparative Learning Ability of Selected Fishes

Abstract

Fourteen species of freshwater fish were trained to execute a simple conditioned response in a shuttle box – to move in response to light to avoid an electrical shock. There was no relation between learning ability and phylogenetic position. Better learners included striped bass (Morone saxatilis), bigmouth buffalo (Ictiohus cyprinellus), common carp (Cyprinus carpio), and channel catfish (Ictalurus punctatus). Bluegill (Lepomis macrochirus) and northern pike (Esoxlucius) were poor learners. Yellow perch (Perca flavescens) and redbelly tilapia (Tilapia zilli) could not be trained. Some fish retained their learned behavior for months, although performance deteriorated with time. Older channel catfish learned better than juveniles, but there was no difference between juvenile and older largemouth bass (Micropterus salmoides). Temperature (18–28 °C) and feeding level (ranging from starvation for 25 d to ad libitum) did not affect learning of channel catfish, but the protozoan disease, ichthyophthiriasis, and perhaps our treatment of fish for the disease retarded it.