A New Species of Dwarf Cichlid Fish with Reversed Sexual Dichromatism from Lac Mai-ndombe, Zaire

Nanochromis transvestitus new species, known only from lac Mai-ndombe, differs from previously described Nanochromis in its sexual dichromatism: mature females acquire striking coloration (vertical white bands on a dark-gray caudal fin) unlike that in females or males of any other species, while males retain relatively drab coloration. N. transvestitus is among the smallest of cichlids: standard length of our largest specimen, a male, is 33.8 mm; sexually mature females are 25.0-32.5 mm.