Molly
Poecilia sphenops
Minimum Tank
20 Gallons
Adult Size
4 inches
Temperature
72-82°F (22-28°C)
pH Range
7.5-8.5
Lifespan
4 years
School Size
4+ fish
About Molly
Mollies are versatile livebearers found naturally in freshwater and brackish coastal habitats from the southern United States through Mexico and Central America. The most popular varieties include the black molly, dalmatian molly, gold dust molly, and the impressive sailfin molly with its large dorsal fin. Mollies are unique among common aquarium fish in their ability to adapt to a wide range of salinities, from pure freshwater to full marine conditions. They are active, social fish that establish loose hierarchies within their groups. Males are easily identified by their gonopodium, a modified anal fin used for reproduction, and they spend much of their time displaying to females.
Care Requirements
Tank Setup
- • Minimum 20-gallon tank required
- • Temperature: 72-82°F (22-28°C)
- • pH: 7.5 - 8.5
- • Category: Livebearer
Diet & Feeding
- • Diet type: Omnivore
- • Feed 1-2 times daily
- • Varied diet recommended
Tank Mate Compatibility
Compatible With
Avoid Keeping With
Care Tips
Expert Tips
Mollies thrive in hard, alkaline water and many keepers find that adding a small amount of aquarium salt improves their health and reduces susceptibility to disease. Keep them at 75-82°F in a tank of at least 20 gallons, as they are active swimmers that need room. Maintain a higher ratio of females to males to reduce stress from constant male attention. Mollies are prone to a condition called molly disease or shimmies, characterized by a rocking, shimmying motion, which is usually caused by poor water quality or inappropriate parameters. Feed a varied diet with plenty of plant-based foods, as they are natural algae grazers. They breed readily, and females can produce 40-100 fry every 4-6 weeks.
Quick Facts
76L
Min Tank (20gal)
10cm
Adult Size (4")
4yr
Lifespan
4+
Min School
Build Your Perfect Community Tank
Find compatible tankmates for your Molly
Related Species You Might Like
Guppy
Poecilia reticulata
Platy
Xiphophorus maculatus
Swordtail
Xiphophorus hellerii
Endler's Livebearer
Poecilia wingei
Sailfin Molly
Poecilia latipinna
Balloon Molly
Poecilia sphenops var.
Tank Mates for Molly
Species from our database with overlapping water parameters, compatible temperaments and a realistic shared tank size.
Swordtail
Xiphophorus hellerii
easy · 20+ gal
Guppy
Poecilia reticulata
easy · 10+ gal
Bronze Corydoras
Corydoras aeneus
easy · 15+ gal
Siamese Algae Eater
Crossocheilus oblongus
easy · 30+ gal
Similar Care Level
Other easy-care species that suit a comparable setup.
Frequently Asked Questions
What size tank does a Molly need?
A Molly needs a minimum tank size of 20 gallons (76 litres). They should be kept in schools of at least 4.
What water parameters does a Molly need?
Molly thrive in water between 72-82°F (22-28°C) with a pH of 7.5-8.5.
Are Molly easy to care for?
Molly are considered easy to care for. They are peaceful fish with a lifespan of about 4 years.
How big do Molly get and what do they eat?
Molly reach about 4 inches and are omnivores. Mollies thrive in hard, alkaline water and many keepers find that adding a small amount of aquarium salt improves their health and reduces susceptibility to disease. Keep them at 75-82°F in a tank of at least 20 gallons, as they are active swimmers that need room. Maintain a higher ratio of females to males to reduce stress from constant male attention. Mollies are prone to a condition called molly disease or shimmies, characterized by a rocking, shimmying motion, which is usually caused by poor water quality or inappropriate parameters. Feed a varied diet with plenty of plant-based foods, as they are natural algae grazers. They breed readily, and females can produce 40-100 fry every 4-6 weeks.