# Mosquitofish profile



## ChilDawg (Apr 30, 2006)

Mosquitofish (_Gambusia affinis_)

(Got any pictures? I'd be happy to use them here...)

Name: Mosquitofish
Other Names: Western Mosquitofish, Western Gambusia
Scientific Name: Gambusia affinis
Family: Poeciliidae

Distribution: Now nearly cosmopolitan, the natural distribution is the Mississippi River basin from Illinois and Indiana south to the Gulf of Mexico. They are also naturally found in the drainages of the Gulf of Mexico west to Mexico.
Length: Females may come close to 3" while males barely exceed 1.5".
Water Temperature: 65 to 80 degrees Fahrenheit (18-27 degrees Celsius) for breeding; may acclimate to temps between 59 to 85 Fahrenheit (15-30 Celsius) otherwise.
Diet: Zooplankton, small insects and random detritus in the wild. Though mosquitofish prefer live foods, they eat foods created for carnivores or standard aquarium fare in captivity. They are especially fond of mosquitoes, hence the common name.
Water Chemistry: They'd love for their water to be moderately-hard or harder (dH > 9)
pH: They prefer slightly alkaline (pH 7-8) conditions; may be acclimated to pH between 6.0 and 8.3.
Lifespan: 3 years

*Species Description* These closely resemble wild-type female guppies in profile. They have pointed heads and gray coloration which becomes a murky white on the ventral surface. All the fins are clear but the dorsal and caudal fins may have parallel bands of black dots (each at nearly the same relative position on their particular fin rays).

*Species Behaviour* These are aggressive fin-nippers with predatory instincts and a marked inability to back down from a challenge.

While they are often cited as shoaling fish, _G. affinis_ will turn on its own kind if underfed. Thankfully, they do well in planted tanks; the plants thereof will help slow the degradation of tank conditions due to necessary overfeeding.

*Natural Conditions* Slow-flowing or standing waters, especially vegetated backwaters and lakes/ponds. They are sometimes found in brackish water.

*Natural Range* Now nearly cosmopolitan, the natural distribution is the Mississippi River basin from Illinois and Indiana south to the Gulf of Mexico. They are also naturally found in the drainages of the Gulf of Mexico west to Mexico.

*Minimum recommended tank size* 10 gallons

*Water Temperature* 65 to 80 degrees Fahrenheit (18-27 degrees Celsius) for breeding; may acclimate to temps between 59 to 85 Fahrenheit (15-30 Celsius) otherwise.

*Water Quality* Their favorite conditions involve slightly alkaline waters that are moderately-hard or harder.

*Sexing* Males have a prominent gonopodium (extension of the anal fin used in copulation) and are generally much smaller and less plump than their female counterparts. Females may also have the gravid spot typical of poecilids.

*Breeding* Males may chase females in order to copulate with them. Several people have mentioned chase scenes in which three or more males show interest in the same female.

Gestation may take three or four weeks and 50-60 young may result from a mating.

Parental _G. affinis_ may be quite predatory, so dense plant cover is required to raise the fry in the same tank as their parents.

Fry may eat newly-hatched _Artemia_ nauplii, finely-crushed flake food and/or microencapsulated foods for livebearers. They may also eat each other, so feeding copious amounts and frequently cleaning their tank may be necessary in order to raise a maximal portion of the fry.

*Feeding* Zooplankton, small insects and random detritus in the wild. Though mosquitofish prefer live foods, they eat foods created for carnivores or standard aquarium fare in captivity. They are especially fond of mosquitoes, hence the common name.

*Miscellaneous Info* Because of their usefulness in biologically controlling mosquitoes in garden ponds, _G. affinis_ may be available from local farm co-ops. Because of their predatory nature, however, they may be banned in several nations and some political sections thereof.

There are way too many synonyms to list here. They may be found at http://www.fishbase.org/Nomenclature/Synon...iesName=affinis.

http://aquatic-hobbyist.com/phpBB2/viewtopic.php?t=6090

I used FishBase and Peterson's "Freshwater Fishes" guide to write this profile.


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## Polypterus (May 4, 2003)

Feel free to use these pics..
If......

You add more caution on the use of Gambusia for Mosquito control..These fish should not be released anywhere outside of there Naturalized range if the body of water is in anyway or could be connect to natural water systems. In addition if you do use Gambusia for mosquito control they should be from a local genetic population..

Below are pics of Gambusia holbrooki which are the more Eastern found Gambusia species in the US. Appearance is identical to G. affinis. Local variations exist in both species but this is their standard appearance.


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