Molly — Fish Profile
Poecilia sphenops
Quick Specs
| Adult Size: | 4.5" |
| Temperament: | peaceful |
| Care Level: | beginner |
| Min Tank Size: | 20 gallons |
| Temperature: | 72-82°F |
| pH Range: | 7.0-8.0 |
| Diet: | omnivore |
| Origin: | Central America |
| Lifespan: | 3-5 years |
Overview
Mollies are adaptable livebearers that can tolerate brackish water. Black mollies are the most popular variety.
Care Guide for Molly
Tank Setup
Molly requires a minimum tank size of 20 gallons. Maintain water temperature between 72°F and 82°F, with a pH range of 7.0 to 8.0. A properly sized tank with adequate filtration and regular water changes is essential for long-term health. When housing Molly with other species, always choose a tank size that accommodates the most demanding fish in the community.
Feeding
Molly is a omnivore feeder. Provide a varied diet appropriate for omnivore species to ensure optimal health and coloration. Feed small portions 2–3 times daily, and remove uneaten food after a few minutes to maintain water quality.
Temperament & Compatibility
This species is classified as peaceful. Molly reaches an adult size of 4.5 inches and has a care level of beginner. Always research compatibility before adding new fish to an established aquarium. Individual temperament can vary, so monitor new introductions closely for the first 48 hours.
Origin & Lifespan
Molly originates from Central America and has an expected lifespan of 3-5 years when kept in proper water conditions with appropriate tank mates and diet.
Compatible Tank Mates
🔴 Risky Tank Mates
Compatibility Results for Molly
All 69 compatibility checks involving Molly:
Recommended for Molly
Tetra Whisper Internal Filter — $19.99Quiet internal filter for 20-gallon tanks
Expert Care Tips for Molly
- Mid-size tank: Molly needs 20+ gallons. Choose a tank at least 2× as long as the fish's adult size (4.5") for adequate swimming room.
- Warm-water species: Molly prefers 72–82°F. Use a reliable submersible heater with a thermostat — avoid temperature swings above 2°F per day.
- Narrow pH tolerance: Molly only tolerates pH 7.0–8.0. Test your tap water before buying — adjusting pH is harder than choosing the right fish for your water.
- Peaceful community fish: Molly works well in community tanks. Still, avoid housing with fish large enough to eat them — a 4.5" fish is vulnerable to anything with a mouth bigger than 2×.
- Acclimation: Always drip-acclimate Molly over 30–45 minutes. Match temperature and pH gradually to prevent osmotic shock.