''Poecilia sphenops'' is a species of fish, of the genus ''

Poecilia ''Poecilia'' is a genus of fishes in the family Poeciliidae of the order Cyprinodontiformes. These livebearers are native to fresh, brackish and salt water in the Americas, and some species in the genus are euryhaline. A few have adapted to livin ...

'', known under the common name molly; to distinguish it from its congeners, it is sometimes called short-finned molly or common molly. They inhabit fresh water streams and coastal brackish and marine waters from

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

. The wild-type fishes are dull, silvery in color. The molly can produce fertile hybrids with many ''Poecilia'' species, most importantly the

sailfin molly The sailfin molly (''Poecilia latipinna'') is a species of fish of the genus ''Poecilia''. They inhabit fresh, brackish, salt, and coastal waters from North Carolina to Texas and the Yucatán Peninsula of Mexico. Taxonomy The sailfin molly was o ...

. The male mollies generally tend to be mildly aggressive. Mollies rank as one of the most popular

feeder fish Feeder fish is the common name for certain types of small, inexpensive fish commonly fed as live food to other captive animals such as predatory fishes (e.g. aquarium sharks, farmed salmon and tuna) or carnivorous aquarium fish (e.g. oscars, ...

due to high growth rate, birth size, reproduction, and brood number.

Biology

Contrary to popular belief, this species of fish is actually a freshwater species, spending little time in brackish water before swimming back to their freshwater biotope. However, fish of the same species have been found in coastal sea waters, brackish swamps and freshwater streams, living and breeding. Mollies appear to be a hardy and highly adaptable species (this has been diluted over years of interbreeding in tank-bred specimens). Mollies are similar in appearance to their livebearer cousins, the platy, swordtail and guppies; the molly tends to be slightly larger and more energetic. Many aquarists note the stronger individuality and aggression in keeping mollies versus

platies Platy is a common name of freshwater fish, freshwater fish in the genus ''Xiphophorus'' that lacks a "sword" at the bottom of their tails. Both species are Live-bearing aquarium fish, livebearers, similar to other fish of the family Poeciliidae, ...

, who appear much more docile.

Size

Standard size of male fish is 3.2″ (8 cm) and female fish is 4.8″ (12 cm).

Varieties

Selective breeding Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant mal ...

over centuries has produced several color variations and different body shapes. *Short-finned molly or common molly: They inhabit fresh water streams and coastal brackish and marine waters of Mexico. The wild-type fishes are dull, silvery in color. The molly can produce fertile hybrids with many ''Poecilia'' species, most importantly the

. The wild form is in fact quite rarely kept, as it has a rather plain silvery coloration suffused with brown and green hues. *Black molly: It is a melanistic breed which are black all over. It is one of the most well-known aquarium fishes and nearly as easy to keep and prolific as guppies. *White molly: A white colored molly. *Golden molly: Nicknamed the "24

karat The fineness of a precious metal object (coin, bar, jewelry, etc.) represents the weight of ''fine metal'' therein, in proportion to the total weight which includes alloying base metals and any impurities. Alloy metals are added to increase hardne ...

". *Balloon molly: This fish has a deformed spine due to a genetic defect that gives it its appearance. Through

selective breeding Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant mal ...

it is now widely available. Balloon mollies can still reproduce and live a normal life comparable to that of other mollies, but it has garnered controversy due to the belief that its defect gives it a shortened lifespan and a susceptibility to health problems. *Lyretail: A breed with an altered caudal fin structure. *Dalmatian molly: A silver colored breed with black speckles.

Gallery

Neon Orange Molly Fish.jpg, A neon orange molly Female Black Molly.jpg, A female black molly 2015-09-13 female spotted molly.jpg, A female spotted molly, 4 years old

References

* * *
Mollies Fish
Detailed information on raising the Molly fish. January 2022 version sphenops Fish described in 1846 Vertebrates of Mexico Live-bearing fish Ovoviviparous fish Taxa named by Achille Valenciennes {{Cyprinodontiformes-stub