PALE AND DARK DICHROMATISM RELATED TO MICROHABITATS IN A HERBIVOROUS TANGANYIKAN CICHLID FISH, TELMATOCHROMIS-TEMPORALIS

Dichromatism and habitat utilization of a small herbivorous cichlid fi sh, Telmatochromis temporalis, were studied in a littoral rocky area o f Lake Tanganyika. Individuals of both sexes had either pale or dark b ody coloration that did not change for long periods. Both sexes defend ed territories from consexuals, and a male had a harem of several fema les. Pale fish had territories in exposed areas and dark fish in shade d ones. Larger fish were dominant over smaller consexuals and occupied well-illuminated areas. When pale and dark fish were kept in areas wi th shaded and lighted backgrounds, respectively, they changed body col our within a few weeks. When pale fish were in well-illuminated areas and dark ones in shaded areas, they were cryptic. Because Telmatochrom is temporalis are very vulnerable prey in coastal areas, dichromatism may function as antipredator camouflage.