Poecilia Velifera (Giant Sailfin Molly)

Poecilia Velifera, also known as the Sailfin Molly belongs to the Poeciliidae family. Other common names of the species are ”giant sailfin”, ”Mexican sailfin molly” and ”Yucatan molly”. Poecilia Velifera may also be known as Molienisia Velifera.
The species is native to Central America (Yucatan peninsula of Mexico) but, has been introduced in different countries. Generally, Mollies occur in freshwater and brackish water streams, ponds, swamps in coastal areas that contains more salt and minerals from other habitats that they exist, such as swamps and canals in tropical and subtropical climates (the Rio Negro in Brazil).
Poecilia Velifera has mainly a grey-green body with other colors such as orange, green-blue. The dorsal and caudal fin have bright spots. The species have been selectively cross-breeding with other molly species, as a result of more colorful domesticated variants or even different body shapes. In truth, you rarely see the wild form in pet-shops, and most of the domesticated varieties are hybrids with different needs. Poecilia Velifera has an average size of 7 inches (18 cm).
The species has a characteristic long and tall dorsal fin. Males have larger dorsal fins than females and male’s anal fins modified to the rod-shaped male’s reproductive organ, the gonopodium. Also, male mollies are slightly smaller and more colorful than female mollies. If cared properly, they can live up to 5 years.
In comparison with other poeciliids, Poecilia velifera is harder to keep. Mollies are more sensitive to sudden temperature drops of more than a degree or two. Furthermore, the addition of salt in the water of mollies prevents many difficulties due to the environmental habits that the species occur. The addition of salt increases the pH and hardness of the water that mollies prefer. Always check if the species have been maintained in brackish water previously so that you can adjust the water conditions in their aquarium. However, the species can thrive in a freshwater tank with the proper requirements. In general, for the maintenance of the species, the condition of the water needs to be stable with a proper diet. They should be kept in hard alkaline water. A pH between 7.5-8.5, with a temperature between 24-27 Celsius, and hardness between 100-150 mg/l, suits the species.
The recommended male to female ratio is 1:2 or 1:3. If male mollies outnumber the female mollies, they get aggressive towards another, plus females get stressed by the constant pursuit from males. It’s better to keep the fish in species-only tanks for optimal care, but because of their social temperament Poecilia Velifera suits for community tanks with species that tolerate hard alkaline water. Some compatible tank-mates are other molly species ( if you don’t want hybridization don’t put them together) and poeciliids such as Platies and Swordtails, guppies (can also hybridize), bottom feeders like Ancistrus, e.t.c. In a brackish tank, mollies can be kept up with gobbies, chromides e.t.c.
Because most livebearers are active species and inhibit in highly oxygenated waters, consume more oxygen and produce more carbon dioxide, with the result that they need a reasonable space in the aquarium. Also, Poecilia Velifera is more sensitive in ammonia and nitrates than other poeciliids leading to that the species need appropriate oxygen and filtration system. Furthermore, live-bearers are best not to be kept in a crowded aquarium. An aquarium of 150 liters (40 gallons) suits a group of 3-4 Poecilia Velifera.
Plants are essential for livebearers, as they provide shelter for stressed fish and their offspring, providing chemical and physical conditions for the growth of microorganisms that can be eaten by the poeciliids.
Mollies are omnivorous, and they can eat prepared food and small live-foods such as brine shrimp, micro-worms, daphnia, white worms, tubifex. In nature, their diet consists of algae as most Mollies are fond of algae, detritus, plant material, small invertebrates, e.t.c. Nutrition needs to include a plant source such as spirulina, boiled vegetables, e.t.c.
The male chases the female, and when the female molly is ready stays immobile for a few seconds until the male fertilizes her. The action is repeated continuously by the male guppy. It’s interesting that poeciliid females can store sperm inside their body for months and get pregnant, without a male.
Although Poecilia Velifera may not eat their young, it’s a well-known fact that livebearers tend to feed on their young. For the best outcome, the male needs to be removed from the aquarium and leave the female alone to give birth. After birth, remove the female molly too. A planted aquarium will increase safety for the fry from the female molly before removal. Like the rest of the poeciliid family, they give birth to live fry. They reproduce better at a temperature near to 26 Celcius (78,8 F). The female Poecilia Velifera gives birth to more than 100 young in one brood. The brood’s number is affected by the age and size of the female molly. Some aquarists say that male sailfin mollies do not develop high dorsal fins in temperatures higher than the species’ range tolerance.

sailfin molly fish, silver orange and striped color in the water glass box. the female is bigger. The ovary is more pronounced. A fish that live and feed on the surface of the water. By eating moss, algae, small water plants.
 “iStock.com/Achisatha Khamsuwan.”


  1. David Alderton 2005, 2008, Encyclopedia of aquarium and pond fish, Published in the United States by DK Publishing, ISBN 978-0-7566-3678-4
  2. Wilfred L. Whitern 1983, Livebearers, ISBN 0876665180
  3. Poecilia velifera. Retrieved from https://www.seriouslyfish.com/species/search/poecilia+velifera
  4. Poecilia velifera. Retrieved from https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=165906#nul
  5. The truth about Mollies. Retrieved from http://www.wetwebmedia.com/fwsubwebindex/mollies.htm
  6. Keeping the Yukatan Sailfin Molly (Poecilia velifera). Retrieved from http://www.nanfa.org/ac/yucatan-sailfin-molly-poecilia-velifera.pdf

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