The Gambusia, from its small name Gambusia affinis, is a small freshwater fish native to the United States that likes to live in schools. It has been successfully introduced in several French regions, including the marshes of the Camargue and certain rivers in the southwest, in order to combat the proliferation of mosquitoes.
Presentation
The gambusia is part of the order Cyprinodontiformes. It is a cousin of the guppies that we commonly find in our aquariums, however its colors are less bright: they vary from gray to light green.
The head is large but ends in a point at the level of the mouth which is provided with many teeth.
The dorsal fin of the gambusia is positioned at the back of the body and is not very developed whereas the caudal fin is larger in the shape of a rounded fan. The ventral fin is located at the base of the tail, it is short and rounded in the female and is transformed in the male into a long pointed organ, the gonopod intended for the copulation. The male is smaller than the female (3,5 cm against 6,5 cm for the female). In addition to their size, they are differentiated by the black spot that the female has on her abdomen.
Habitat and feeding
Native of the hot zones of the United States, the gambusia has incredible faculties of adaptation, what was worth to him to be introduced from share the world to fight against the plague of the malaria and other diseases carried by the mosquitos. Its preferred waters are fresh but it is not uncommon to find it in brackish waters or in saturated waters with very low oxygen content.
The gambusia is found in large numbers in Mexico, Cuba, Jamaica and Nicaragua. It can be described as robust and combative: it must often be isolated when it lives in an aquarium because it tends to attack the fins of other fish, it can even eat its own young.
Gambusia feed on mosquito larvae, bloodworms, water fleas or even tadpoles.
Life cycle
The reproduction period of the gambusir is from April to October. Males insert their gonopod into the genital opening of females and fertilize the eggs.
The fertilized females lay fry over a long period of time with intervals of a few weeks between each spawning.
The fry, less than 10 mm in size, are just born and disperse into the vegetation where they continue to develop until they reach sexual maturity six months later.
The life span of the Gambusia is approximately two years.
