- The mosquito fish is a small fish, with the females generally below 3 inches and the males below 2 inches. Females are also rounder in shape and have a rounded anal fin (as compared to the male's anal fin, which is slightly elongated and pointed). Mosquito fish are silvery in color, with a lighter underside, but may alter their color slightly over time to better blend with their habitat.
- While mosquito larvae are the meal of choice for this fish, they will feed on any insect larvae or small insects that enter the pond, making them the perfect insect control. They also occasionally feed on algae, helping to keep the pond's ecosystem balanced. If there is not enough natural food in the pond to feed the mosquito fish, they should be supplemented with a quality brand of flaked fish food.
- While mosquito fish are native to freshwater lakes and streams in the southern and eastern United States, the fish may now have the widest range of any freshwater fish species due to intentional introduction to freshwater bodies as a means of controlling mosquitoes. In fact, it is considered a pest species in some areas, where it outcompetes local species for food. The mosquito fish can endure temperature ranges from nearly freezing to over 100 degrees F, making it aptly suited for a wide range of habitats.
- Mosquito fish are livebearers, meaning they give birth to live offspring rather than laying eggs. This strategy makes them extremely prolific, as the young enter the world able to feed and survive on their own, allowing the parents to continue reproducing without having to care for eggs. Males have a specialized anal fin used in breeding, called the gonopodium. Mosquito fish will cannibalize their young, which should be provided with plenty of hiding places until they can survive in open water.
- Because mosquito fish are so small, they will become meals for any larger fish housed in the same pond unless they are provided sufficient cover in the form of rocks and plant material. Additionally, mosquito fish should never be introduced into natural bodies of water that may allow access to wild or uncultivated streams and lakes where the species may become a pest.