Telling males from females is one of the most common problems a beginning cichlid hobbyist faces. For some species, males and females are readily distinguishable by color, size or shape. For others it is difficult or even impossible to tell the sexes apart in nonbreeding individuals. We call differences between the sexes "sexual dimorphism" and when there is no difference, we say they are "monomorphic". Oscars are the most monomorphic cichlids I know of, with no visual differences between males and females.

Probably the most accurate means for telling the sexes apart is a technique known as "venting", i.e. examining the vent region of a fish to determine its sex. For an excellent discussion and photographs on "venting", take a look at GARY KRATOCHVIL's page.

The most difficult part of venting is that you need to have the fish in-hand in order to look closely at the vent region. This isn't always possible.

Are there other ways of determining the sex of a fish? Yes. But, there are also many myths that must be avoided. Determining the sex also depends to a large degree on what "type" of cichlid you are looking at, e.g., Central American, West African, mbuna from Lake Malawi etc.

Central American cichlids

Using the convict cichlid as our sample organism for this group, there are several characteristics that allow you to distingui ...