Prominent sexual dimorphism, such as distinct color differences, is a character
on which researchers rely when making in situ observations. Distinguishing characters
between the sexes are often used in laboratory experiments in order to minimize the
handling of fishes. Male and female Melanochromis auratus, a maternal mouth
brooding cichlid from Lake Malawi, are colored differently. Male fish are mostly black
with a light blue midlateral band, whereas female fish are mostly yellow with a dark
midlateral band. Although a random sample of 119 M. auratus from Lake Malawi
are consistent with this description, two female M. auratus in the laboratory
are black fish with midlateral bands.