
Source: Wikimedia Commons
Livebearing fish like platy but slightly larger. Many varieties including balloon and black molly. Tolerates brackish water.
Mollies (Poecilia sphenops and related species) are livebearing fish widely distributed from the Gulf Coast of Mexico to northern South America, remarkable for their ability to thrive in both freshwater and brackish water environments. Reaching 6–12 cm, they are available in numerous selectively bred color forms — black, white, gold, dalmatian — including the popular 'balloon' variety with its distinctively rounded abdomen. Mollies prefer slightly alkaline, moderately hard water and benefit from the addition of a small amount of aquarium salt (3–5 g/L), which enhances vitality and disease resistance. Optimal temperature is 25–28°C. Generally peaceful, their relatively larger size can intimidate small fish, so tankmates of similar size are preferred. As prolific livebearers, females produce fry regularly, requiring management to prevent overcrowding. Mollies have a notably herbivorous tendency — spirulina flakes, blanched spinach, and algae wafers complement their diet alongside standard tropical fish foods. Their appetite for algae also provides a minor but appreciated cleaning function in planted aquariums.
Origin
coastal rivers and brackish zones from the Gulf Coast of Mexico to northern South America
Lifespan
3-5 years
Size
6-12cm
Temperature
22〜28℃
Pellets, algae, frozen food
Sources: FishBase / Seriously Fish
Edited & verified by: br-choku editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Primary sources
「モーリー」は総称。代表種 Poecilia sphenops で確認。Poecilia 属に CITES 掲載種なし。
Sources: FishBase / Seriously Fish / CITES Appendices (Checklist)
Regulations may change. Always verify the latest information with the relevant authorities.
Find listings for this species
45cm+ recommended
Prefers alkaline hard water. Small salt addition beneficial
Livebearing — breeds easily
Peaceful but males may compete
Susceptible to ich — keep temperature stable
Beginner. This is a beginner-friendly species. No special equipment or experience is required, and it can be kept successfully with basic care setup.
The ideal temperature for Molly is 22〜28℃. Avoid sudden temperature changes and maintain a stable environment.
The average lifespan of Molly is 3-5 years. With proper care and nutrition, they can live a long and healthy life.
Molly typically reaches 6-12cm as an adult. Size may vary depending on care conditions and individual genetics.
Molly feeds on: Pellets, algae, frozen food. Aim for a balanced diet with appropriate feeding frequency.
The price of Molly varies significantly depending on morph, size, and lineage. Check our market price page for the latest pricing information.
Last updated: June 23, 2026