wpjk  (12 years ago)
Male or Female?
How to sex cichlids.

Text, photos and graphics by GARY KRATOCHVIL
©1997 Gary Kratochvil, Exotic Tropicals

Venting diagram One of the questions I am most commonly asked is how to determine the sex of fish. The only positive way to determine the sex of sexually monomorphic species (males and females look similar) is by examination of the vent. This practice is commonly referred to as venting. What is the vent and where is it? The vent is the opening between the anus and the anal fin where the fish will excrete either eggs or sperm. The vent is also referred to as the genital papilla. For females the term ovipositor (egg tube) also refers to the vent. The photo on the left shows you where to look. In this article most of the photos are taken with the fish oriented with the head of the fish pointing away from you and and turned upside down. In addition all specimens photographed were sexually mature adults. With experience you will be able to determine the sex of some species as early as three to four months of age with a high degree of accuracy.

The first six species pictured below are of mouthbrooding cichlids. Female mouthbrooders will lay an egg which is much larger in diameter than their substrate egg laying counterparts. Therefore the diameter of the vent is also much larger and easier to distinguish. Just look at the photos of the Tropheus moorii and Petrochromis trewavasae to see how easy these species are to sex. Conversely some substrate egg layers can be a bit more difficult to distinguish. Neolamprologus tretocephalus for example does not have near the differences in vent size and will require a little more experience to determine males from females. In some cases there will also be a pigment difference between the male and female vent. Julidochromis regani is an example of a species in which the male will have an elongated tapered papilla. In these species you can move your finger across the vent from left to right and the papilla will also move. In the photo below of J. regani I moved