Mollies are a very diverse fish- a huge variety of both wild species exists, as well as domesticated fancy strains. FishBase.org lists more than 20 wild species. All are native to North, Central, South America and surrounding islands. Mollies are found primarily in freshwater, but also commonly in brackish and even saltwater environments. Mollies will benefit from ½ tsp. non-iodized salt per gallon of water; a dosage which should not harm most other fish or plants. Mollies are omnivores but need vegetable-rich diets. Mollies will eat many aquatic plants.
The Mexican Sailfin pictured (Poecilia latipinna) is one of the largest species- able to grow up to 7”. Sailfins (P. velifera) can grow to 4.75.” Black and Short-finned Mollies (P. sphenops) are the smallest, reaching only 2.3.” A minimum of a 20 gallon Long tank is needed for the smaller species, and a 40 gal minimum for Sailfins. They are peaceful community fish. Mollies are best kept in trios, at least 2 females per 1 male. Males are smaller and thinner than females, and possess the gonopodium anal fin common to most livebearers. They are prolific livebearers, though less so than Guppies or Platies.
I bred black mollies excellently and they grew quick too. I recently bought a black swordtail molly and it now eats the plec tabs I put in for the bottom feeders. Their colours are too different, sailfin mollies seem to have a more diverse colour range than balloon mollies though dalmation mollies have beautiful babies.
