One of the main reason that every hobbyist would want to own mollies is for their easy nature and character.

Why do you need a beginner’s guide for the most common fish in the aquarium hobby? They are not only the most common fish in the aquarium hobby but also livebearers and this beginner’s guide has precise information about keeping and raising healthy molly.

Molly Fish – Overview

Common NameMollies, Shortfin Molly
Scientific NamePoecilia sphenops
Habitat or OriginSpecies are native of the brackish coastal waters of Mexico.
Average SizeThe male grows up to 8cm or 3.2 inches and the female grows up to 12 Cm or 4.8 Inches.
ColorationThe natural coloration of Molly fish is Dull Silver. However, the captive-bred ones are available in golden, silver-white, black, dalmatian (black and white mixed)
Life SpanMollies live up to 4 years.
DietIn the wild, they feed on mosquito larvae and algae. In captivity, they are fed frozen bloodworms, flakes, and pellets. You can also give them small pieces of lettuce.
Gender IdentificationMales have longer and bigger fins and females have short and wider bodies. Males have modified anal fins which is very clearly visible in adults.
BehaviorNot Aggressive in nature. However, Male tend to be aggressive during mating with a female, and females post-delivery of babies tend to be aggressive.
CompatibilityMollies could be kept with other Livebearers such as Guppies, Swordtails, Platies.
Ideal Tank ConditionsWe recommend a minimum of 25 Gallon tank with good filtration. Would be ideal to keep them in a planted aquarium as they love to feed on algae.
Water ParametersIdeal pH is 6.7 to 8.5, water hardness should be between 20-30 kH and water temperature is between 72 to 82 Degree Farrenheit or 25 to 28 Degree Celcius.
BreedingBreeding is very easy, you will have to identify a healthy male and introduce 3 to 4 females (1:3) ratio in a densely planted tank. Make sure the water temperature is close to 82 Farrenheit. Mollies being Livebearers, the female mollies carry the young ones for a period of 45 to 60 days. They generally deliver 45 to 60 fries during one delivery. As soon as the fries are born, they freely swim and it is advised to move the parent mollies or young fries to a different tank.
Common DiseasesWhite spots,finrot, mouth fungus, swim bladder disease are the most common ones and this could be avoided by keeping the tank clean and water parameters intact.
Approximate CostThis depends on the country and the quality of the strain, in USA the average price is between 2 USD to 5 USD and in Asian countries, it is available at 1/3 of the price of USA.
What to look when buyingCarefully examine for any fin damages or bent bodies, look for any infections (like white spots).
Species in the MarketThese are some of the popular species of Siamese fighting fish available in the local fish stores – Black molly, golden molly, white molly, balloon molly, lyretail molly, short-finned molly, and dalmatian molly.

Different types of Molly Fishes


  1.  Matamoros, W. (2019). Poecilia sphenopsIUCN Red List of Threatened Species
  2. e.T191753A2002434. doi:10.2305/IUCN.UK.2019-2.RLTS.T191753A2002434.en.
  3. Froese, Rainer, and Pauly, Daniel, eds. (2019). Poeclia sphenops in FishBase. August 2019 version.
  4. “Poecilia sphenops”Integrated Taxonomic Information System.
  5. Froese, Rainer, and Pauly, Daniel, eds. (2005). Poecilia sphenops in FishBase.