Molly Fish Tankmates: Best & Worst Companions
Mollies are peaceful community fish, but choosing tankmates isn't just about temperament — water chemistry compatibility is the most important factor. Mollies prefer hard, alkaline water, and species that require soft, acidic conditions are a poor match regardless of how peaceful they are. Get the parameters right first, then consider behavior.
For full care information, see the Molly Fish Care Guide.
Water Parameter Compatibility First
Mollies do best in moderately hard to hard water with a pH of 7.5–8.5. Before adding any species to a molly tank, check its water parameter requirements. A fish that's peaceful but needs soft, acidic water is not a suitable molly tankmate — one of them will always be kept in suboptimal conditions.
The best molly tankmates are other livebearers and species that naturally tolerate or prefer harder, more alkaline water.
Compatibility by Species
Can mollies live with guppies?
Yes — one of the best combinations. Guppies share similar water parameter preferences and are peaceful. Male guppies and male mollies may occasionally display toward each other but rarely cause problems in a properly sized tank. Keep appropriate female ratios for both species.
Can mollies live with platies?
Yes — the most natural pairing. Platies have nearly identical care requirements to mollies — same water parameters, same temperament, same diet. This is the lowest-risk community combination for a molly tank.
Can mollies live with swordtails?
Yes. Swordtails are another livebearer with compatible water parameters and peaceful temperament. A good fit in a larger community tank.
Can mollies live with tetras?
Depends on the species. Compatibility varies considerably by tetra species and source population. Many tetras prefer softer, more acidic water than mollies. Choose species whose hardness and pH requirements genuinely overlap with your mollies rather than altering the aquarium to an arbitrary compromise value. Research the specific tetra before combining.
Can mollies live with angelfish?
Possible in larger tanks, with caveats. Angelfish can work with mollies in a 40+ gallon tank if water parameters are compatible — angelfish prefer slightly softer water than mollies ideally, but can adapt to neutral-to-slightly-alkaline conditions. The bigger risk is that large angelfish may eat small molly fry, and angelfish can be nippy toward long-finned fish. Monitor carefully.
Can mollies live with bettas?
Generally not recommended. Bettas prefer softer, more acidic water than mollies, creating a parameter conflict. Male bettas can also be aggressive toward other fish, particularly those with flowing fins like lyretail mollies. A species-specific betta tank is a better choice.
Can mollies live with goldfish?
No. Goldfish are coldwater fish that do best at 65–72°F — well below the 76–80°F that mollies need. Temperature requirements alone make this incompatible.
Can mollies live with shrimp?
With caution. Adult large shrimp (Amano, large cherry shrimp) may coexist with mollies, but mollies will eat small shrimp and shrimp fry. A heavily planted tank provides some cover, but a dedicated shrimp tank is safer if shrimp survival matters to you.
Can mollies live with corydoras?
Often yes, but check species parameters. Many Corydoras species can tolerate harder water, though preferences vary by species. They're peaceful, occupy the bottom of the tank, and don't compete with mollies for space. Research the specific Corydoras species before combining.
Can mollies live with bristlenose plecos?
Yes, in larger tanks. Bristlenose Plecos tolerate harder water and are peaceful. A useful algae grazer in a molly community tank. Needs 29+ gallons.
Species to Avoid
Fin Nippers
Avoid species known to nip fins, particularly if you're keeping lyretail or balloon mollies.
- Tiger Barbs
- Serpae Tetras
Soft-Water Species
Species that require soft, acidic water are a poor match regardless of temperament.
- Discus
- Most wild-type South American cichlids
- Cardinal Tetras (prefer softer, more acidic water)
Aggressive or Predatory Species
Any fish large enough to eat mollies or aggressive enough to harass them is unsuitable. Mollies are not equipped to defend themselves against cichlid aggression or predatory behavior.
Molly-to-Molly Dynamics
Keep at least 2–3 females per male. Males will persistently pursue females — without enough females to distribute attention, individual females are harassed constantly. This is the most important intraspecies consideration for molly groups.
Multiple males can coexist but may display and compete with each other, particularly in smaller tanks. A larger tank with visual breaks reduces conflict.