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Gambusia holbrooki
Eastern Mosquitofish, Eastern Gambusia

 Age of Aquariums > Freshwater Fish > Eastern Mosquitofish - Gambusia holbrooki

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Gambusia_holbrooki_1.jpg (43kb)
Photo Credit: Butch

Name: Gambusia holbrooki
Size TankpHTemp
Origin: Eastern USA
7 cm 40 L 7.5 23C


Eastern Mosquitofish (Gambusia holbrooki), is an aggressive live bearing species, which inhabits eastern United States. These Eastern Mosquitofish are the most common "wild type" of livebearers that are available in the aquarium trade. These fish can be found in most places of the world, because of the introduction to non native water systems for mosquito control. The mosquito fish are actually useless fish because they will eat young fry of other fishes and other aquatic creatures instead mosquito larva. The eastern mosquitofishes are more common contaminants in the feeder shipments from the south United States fish farms. They are very aggressive towards other species if kept in the community tank. In my opinion, they are better kept in a species tank than a community tank. The mosquitofish are murderous fish, often nipping the fins off of other fishes till the tankmates tumble to their death.

Gambusia_holbrooki_2.jpg I kept 15 mosquitofish in a 110 liter long tank with lots of plants (Java moss, elodea, swords and some duckweed). The plants are there for a reason: the mosquitofish often chase each other and the plants provide hiding places for a chasee. I fed my gambusia with frozen bloodworms, dried bloodworms and red flakes as gambusia prefer protein over the green matter, but they are omnivores, which means they eat both animals and plants. So they are not picky eaters, they can do fine on flakes, pellets and any food you can give to them.

Breeding the mosquitofish in the aquarium is easy, same thing as guppies. The females are larger than males and often have a black gravid spot near the anal fin. The males are smaller than females and have a stick-like fin called gonopodium which transfers the sperm and fertilizes the eggs inside the females. The pregnant females will give birth four to six weeks later. She will expel 10 to 60 fry in a single batch. A female can have six to seven batches from a single mate. It's easy to breed gambusia but the negative is that the parents are relentless fry hunters, looking for any fry around the tank to eat the fry. So I had a 40 L full of Java moss to house the female gambusia to give birth in the tank. When she is done, I removed the female from the 40 L to the 110 L tank. I fed frozen brine shrimp and First Bites to the newborn fry till they were a month old, enough to eat frozen bloodworms. Make sure you dont overfeed the fry, otherwise you have to clean up uneaten foods left in the tank as it could downgrade the water quality.

They are hardy and adaptable to any water conditions from full saltwater to full freshwater. Some populations are brackish and some populations can survive under the freezing ice in a few areas. But they do fine at temperatures around 20C. Good native fish to start as the mosquitofish are very easy to take care of.

Contributed by Butch

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