Molly (Poecilia sphenops) is a beginner-level freshwater fish that needs at least 20 gallons and 72-82°F. A hardy livebearer that likes hard, alkaline water and a little vegetable matter in its diet. Some keepers add a little aquarium salt, but it is not required for most freshwater tanks.
Care facts at a glance
| Scientific name | Poecilia sphenops |
|---|---|
| Family | Poeciliidae |
| Origin | Central America and Mexico |
| Adult size | 4 in |
| Minimum tank | 20 gallons |
| Temperature | 72-82°F |
| pH | 7.5-8.5 |
| Temperament | Peaceful |
| Social behavior | Groups; more females than males |
| Swim level | Mid to upper |
| Difficulty | Beginner |
| Diet | Omnivore: flakes, algae, veggie foods |
| Typical lifespan | 3-5 years |
Quick tips
- Needs hard, alkaline water.
- Offer algae wafers or blanched veggies.
San Diego water
Naturally suited to San Diego's hard, alkaline tap water once it is dechlorinated (the city uses chloramine, so use a conditioner that handles it). Learn the numbers in our San Diego tap water guide.
Before you buy
Make sure your tank is cycled (how to cycle a tank), check your numbers with the water testing guide, and use the compatibility guide to check tankmates. These are general ranges; individual fish and local water vary.
Find it at Pet Zone
Pet Zone Tropical Fish is a San Diego aquarium store with two locations. Stock changes daily, so call ahead if you are after a specific species or plant. Shop online at petzonesd.com.
4160 Convoy St, San Diego, CA 92111
(858) 987-0309
Open daily, 10am-6pm
Aquascaping, planted tanks
4266 University Ave, San Diego, CA 92105
(619) 283-1812
Closed Monday; Tue-Fri 10:30am-6pm, Sat 11am-6pm, Sun 11am-4pm
Monster fish, koi