Behavioral assessment of the visual capabilities of fishes

A rich repertoire of behavioral methods is available to assay visual functions and their adaptive changes in fishes. Most methods are available for adult fishes, but many can be applied in larvae and have enabled powerful genetic and imaging approaches. Some methods involve training the fish—from quick classical conditioning to rather sophisticated paradigms. Others require no training at all and make use of reflexes, such as the dorsal light reflex, and a variety of naturally occurring visual behaviors. By illustrating them with selected examples we hope to give an idea of how they are best employed.