Let’s look at these 3 species of freshwater fish commonly referred to as “Mosquito Fish”. This poorly attached “nickname” has confused fish and wildlife personnel for years, so here is the difference once and for all.
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Heterandria Affinis, Too mean for Fountins, Invasive for Nature!
Genus: Gambusia Poey
Species: Heterandria Affinis 1854
Range: Gulf drainage, from Texas to Alabama and into Florida
Size: 2 ½ inches, breeds at 2 inches
Temperament: This species is predaceous and active for its size, it will reduce the fins of other fishes to shreds and eat the fry of anything it can fit in its ravenous mouth. This fish is always hungry for live food and is always ready for a fight with fish sometimes 4 times its size.
Temperature Requirements: Almost none, once established, this fish can survive temperatures of just above freezing to well over 90F, which means it can live beneath the ice and last through winter in most climate, once established this fish is almost impossible to eradicate.
Sex Differences: Male has the gonopodium and, like the guppy, is quite a bit smaller and thinner than the female, but unlike the guppy, the male is colorless and dull greenish brown.
Breeding Procedure: Considered to be among the most difficult of livebearers to breed in captivity, this species also has a great appetite for its own young. It can stand all types of foul water conditions, poor food, and overcrowding. It is pretty much indestructible in the wild, but not so much in an aquarium, it seems to need “old” water and “live critters” of plenty to eat. The Young are born over a period of 3 to 4 days and total only around 24 per brood, broods are around 6 to 8 weeks apart.
Positives for Mosquito Control: This is a Mosquitofish that does wonders on mosquito larvae, eating its own weight of them per day. This fish has been sent to many parts of the tropical world for use in mosquito extermination.
Negatives for Mosquito Control: This is an invasive species that will absolutely eat any live fry they can fit in their mouth, including bass fry, trout fry, anything they can eat, not just mosquito larva. Unlike the Guppy and the H Formosa, the can survive very cold temperatures and bad water conditions, so once introduced to a water system, it is difficult if not impossible to remove them.
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Heterandria Agassiz, Interesting in Aquariums, Small for Lakes and Ponds
Genus: Heterandria Agassiz
Species: Hererandria Formosa Agassiz 1859
Range: North Carolina to Florida
Size: Female 1 inch, male ¼ inch; breed at this size.
Temperament: Suitable for a small tank with Guppies, otherwise best kept by itself because of small size.
Temperature Requirements: 50 to 90F
Sex Differences: Male has gonopodium and is so small that male it is taken for a fry if not observed closely.
Breeding Procedure: This livebearer is easily bred. The parents when well-fed with live food do not pay much attention to their fry. During the breeding season, spring to midsummer, females will drop two or three fry per day for about 10 days or so. They will stop for 4 weeks and then start dropping again. The fry are easily raised, first on infusoria then on baby brine shrimp and then on Daphnia.
Positives for Mosquito Control: None
Negatives for Mosquito Control: It is difficult to imagine this species as a Mosquito Fish since the male is barely larger than a full-grown mosquito larva itself. This fish got its nickname not for its habit of eating mosquito larva, but for its small size. This fish is erroneously sold online and in lake supply as Mosquito Fish, it is not a mosquito larva eater and will do absolutely no good for mosquito control. It will eat an enormous amount of Daphnia if supplied with these little animals, and if given them regularly they will reproduce in great numbers. Even the females never grow large enough to eat a full-grown mosquito larva.
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Gambusia Holbrooki, True Mosquito Fish, First Line of Defence
Family: Poeciliidae Genus: Gambusia Holbrooki (named in honor of the naturalist J.E. Holbrook) Species: Gambusia holbrooki Girard 1859
Range: New Jersey to Florida.
Size: 2 inches; breeds at 1 ½ inches.
Temperament: This species is best kept with itself because in an aquarium it will shred the fins of fish 4 times its size. This is the true mosquito fish, but it is meant for the wild, not for community aquariums. This is a nasty little fish, It knows how to fight and it will win. It will eat any fry or small fish it can fit in its mouth, including its own fry at birth. Not a good choice for outdoor Goldfish pond, these little fish will shred fins.
Temperature Requirements: Above freezing to 88F, can survive under the ice.
Sex Differences: The male has the gonopodium.
Breeding Procedure: This species can be easily recognized by the males very long gonopodium, almost a long as the distance from the tip of his head to the center of his groin. Females give birth only during the months of May to October. The fry are about 1/3 of an inch long and can eat anything at birth. Due to their size, the fry are not often eaten by the adults, though females will occasionally eat a few at birth. A large female can have broods of 30 to 60 fry every 6 weeks born over 2 to 3 days. In nature the ratio of 6 females to 1 male is usual. Maturity is reached in about 4 months depending on water temperatures and food supply, so only fry born in early spring can reproduce before breeding season ends in the fall.
Positives for Mosquito Control: This is possibly the best mosquito eater of all fish for its size. One individual fish has been credited by S.F. Hildebrand as having eaten 165 mosquito larvae in 12 hours! The fish is considerably smaller than Heterandria affinis so its tendency to eat fry of native fish is much less prevalent. It has a wide range of temperature tolerance, can even survive through winters with lakes and ponds frozen over as long as water exists beneath. This is a good choice for wild lake and pond mosquito control, but not ornamental pond mosquito control, this fish will shred fins of ornamental fish, no matter how big the ornamental fish.
Negatives for Mosquito Control: This species must be bought in sufficient number to control the mosquito population, and reproduction relied upon for sustaining the population only. Some damage to native species, but not enough to effect the overall population. This fish is not the best answer for ornamental ponds and fountains, it does not play well with ornamental fish such as goldfish or guppies.
Note: Gambusia Holbrooki Girard is the True Mosquito Fish and is a good choice for Mosquito population in natural ponds and lakes. It is not a good choice for backyard ponds and fountains, that Mosquito Fish is the Guppy!
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Poecilia riticulata (Guppy) Great Mosquito Control for Back Yard Ponds
Family: Poeciliidae Genus: Lebistes Filippi Species: Guppy/ Poecilia riticulata 1860
Range: Venezuela, Trinidad, and Barbados. The Guppy was introduced over 100 years ago into many localities of the world as mosquito-control fish, now “native” to every tropical and sub-tropical climate over every continent on earth.
Temperament: A peaceful species well suited for any environment, no damage to native species, not prone to eating native fry. Also good with any and all ornamental fish, and good in home community aquariums as well. Iives in all forms of water from running streams and active fountains to ponds and lakes even stagnant pools.
Temperature Requirement: 58 – 90F ideal 72F average. Below temperatures of 58F, the Guppy will simply lay over on its side and die quietly, no struggle no pain, just like falling asleep.
Breeding Procedure: The males of this species may be born with any of a kaleidoscope of color, even raw in natural form, they are brightly colored and no two males are the same, at full maturity, the common Guppy male is 1 inch in length. The female is a dull green /brown, much larger than the male, up to 2 ½ inches. The female guppy is capable of having a brood every 4 weeks and once impregnated she can have 5 or more broods without benefit of a male again. The young can reach sexual maturity in a well-fed pond in 5 to 6 weeks and give birth by the 9th week of life! Broods are anywhere from 45 to over 180 fry all born at once, the fry eat anything and at birth are fully functioning self-sufficient fish.
Positives for Mosquito Control: The Guppy is a cheap easy to introduce into any body of water, eats its weight in mosquito larva every day. It breeds freely, gives birth to large broods of self-sufficient young, which are themselves able to give birth in 9 weeks, making population of lakes quick and inexpensive in one season. Guppies eat anything, rarely eat native fish fry, each guppy eat their weight in mosquito larva each day, even the fry eat hatchling mosquito larva at birth. If in a cold climate, they simply disappear from the ecosystem at the end of the mosquito season, making it your choice to re-introduce them the following season. Fantastic for ornamental ponds and fountains, survive in the smallest of fountains or the largest of Koi ponds, never interfere with other ornamental fish, and actually look good.
Negatives for Mosquito Control: Guppies are a rather delicate fish compared to the Gambusia Holbrookii Girard, may not do as well in a large well-stocked lake or pond. They will die at the end of the season where the temperature of water goes below 58F.
For more Information on Zika and how to make your Backyard Water Features save
If looking for the Ideal mosquito control in a backyard water feature, fountain, pond or small water plant container, than the Guppy is your answer. If on the other hand you are looking for mosquito control long term in a large lake system over many years you may want to look to the Gambusia Holbrookii, it is the least invasive, will survive cold weather and is least likely to disturb natural species. We have a problem with the Zika Virus and it is not going away soon, you must guard you family against this menus, your back yard water features can be protected by the reliable guppy, find out more HERE, HERE and HERE.