AY Honors/Fishes/Answer Key

Poecilia sphenops is a species of fish, of the genus Poecilia, known under the common name Molly. They inhabit the coastal brackish and marine waters of Mexico. The wild-type fish are a dull silvery color, often sprinkled black all over.

This species is one of the ancestors of the black mollies, a number of melanistic breeds 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 (for optimal health and breeding success, they demand fresh vegetable food like algae). There are several other popular breeds, like the golden molly nicknamed "24 karat", or the balloon molly, which however has a deformed spine and a decreased lifespan due to the associated health problems. Also, breeds with altered caudal fin structures like lyretails exist. The wild form is in fact quite rarely kept, as it has a rather plain silvery coloration suffused with brown and green hues. If given good care with ample sunlight, high water temperatures and fresh vegetables, they will, however, prove charming fish who make up for their somewhat plain coloration with their lively behavior.

The common molly can produce fertile hybrids with many Poecilia species, most importantly the sailfin molly. In the case of black hybrids, they are called midnight molly. These are very popular due to their impressive dorsal fins, but require a bit more attention and have a somewhat decreased lifespan - though certainly not as much as the deformed breeds.

The male black mollies generally tend to be aggressive. Although they are compatible tankmates with fish like the tiger barbs, they will attack them.

Gallery of breeds

• 

  Female and (upper left) male silver molly

• 

  Artist's image of male double swordtail black molly. Note rather small dorsal fin.

• 

  Male gold mollies look very similar to some variable platyfish

• 

  Gravid female marble molly

References

• Template:ITIS
• Template:FishBase species

Template:Commons

Template:Cyprinodontiformes-stub