Gonopod

Modified anal fin in view of fertilization in the oviparous and oviviviparous fish male.

Gonopod is an anatomical structure present in certain fish from the cichlid family. This structure is on the belly of the animal and is used mainly for reproduction.

In males, the gonopod is an elongated and often colorful appendix which is used to deposit the sperm on the eggs of the female during fertilization. It can be located on the lower part of the head, on the thorax or on the abdomen, depending on the species.

In females, the gonopod is less developed and does not play such an important role in reproduction.

Gonopod is a secondary sexual character, that is to say that it is not directly linked to reproduction, but that it contributes to sexual selection by attracting partners and facilitating reproduction.

Cichlids are very diverse fish and the gonopod can be very different depending on the species. Some species have very long and developed gonopods, while others have shorter and less visible gonopods.

Gonopod is an important character for aquarium breeders and can be used to identify the males and females of certain species. However, it is important to note that the determination of the sex of the fish is not always as simple and that other characters can be used in addition, such as the shape of the caudal fin or the color of the eggs in females.

In summary, the gonopod is an anatomical structure present in certain fish of the cichlid family, mainly in males, which is used for reproduction. It is a secondary sexual character that can be used to identify males and females of certain species.