Gambusia Affinis

Datasheet

General Description

The Western Mosquitofish, scientifically known as Gambusia affinis, was previously believed to be the same species as the Eastern Mosquitofish but has been identified as a distinct species. This fish species is sturdy and adaptable, often introduced globally for mosquito population control, although it can have negative impacts on ecosystems due to its predatory nature. Male individuals of G. affinis lack a serrated leading ray on the gonopodium, and typically have six dorsal rays, distinguishing them from G. holbrooki.

Aquarium Setup

For Western Mosquitofish, a suitable aquarium setup includes a gently-filtered tank with abundant vegetation. This type of tank not only reduces the fish's shyness but also provides hiding places for the fry away from adult fish. Additional decorations can be incorporated as preferred, meeting the specific water conditions mentioned in the species profile.

Behaviour

Due to its hyper-competitive nature, the Western Mosquitofish is not ideal for a community tank. This species displays aggressive behaviors such as food stealing, intimidating smaller fish, and fin-nipping. It is recommended to keep them in a species-only tank, as having more than one male can lead to constant bickering among the individuals.

Feeding and Diet

The Western Mosquitofish is an omnivorous species that readily accepts various types of food. It particularly enjoys small live or frozen options like brine shrimp and Daphnia. A balanced diet for this fish should include a substantial portion of these preferred food sources.

Reproduction & Dimorphism

Reproduction in Western Mosquitofish is uncomplicated, with breeding almost inevitable if both male and female fish are present. It is advised to isolate gravid females to a separate tank for fry to survive, as the parents tend to consume them. The gestation period lasts approximately four weeks, yielding 10 to 100 fry. The male fish are considerably smaller than the females and possess a gonopodium for breeding purposes.

Habitat and Distribution

In its natural habitat, the Western Mosquitofish is commonly found in shallow, densely vegetated areas of still or slow-moving water bodies. It can also adapt to brackish conditions in certain regions. While originally from Mexico and southern USA, thriving populations of this species exist in more than 60 countries worldwide, where it is introduced for biological mosquito control.