Can bettas live with mollies?

Verdict
Yes, with care

Yes, with care. Bettas and mollies can share a tank, but watch one thing. Water chemistry is a squeeze. The only pH that suits both is around 7.5.

BettaBetta76–82°F · pH 6.5–7.5 MollyMolly72–82°F · pH 7.5–8.5

What to watch

What works

Water side by side

55°60°65°70°75°80°85°90°Both: 76–82°Betta 76–82°Molly 72–82°
The green band is the temperature range both can live in.
456789Both: 7.5Betta 6.5–7.5Molly 7.5–8.5
The green band is the pH both tolerate.

Size to scale

Betta · 2.5 inMolly · 4 in0"1"2"3"4"5"6"
Adult length in an aquarium. A fish can swallow anything that fits in its mouth, roughly a third to half its own length for predators.

Care at a glance

BettaMolly
Temperature76–82 °F72–82 °F
pH6.5–7.57.5–8.5
Adult size2.5 in4.0 in
Minimum tank5 gal20 gal
TemperamentSemi-aggressivePeaceful
Swims atTopTop
GroupOne per tankGroups of 3+
DietCarnivoreOmnivore

Better tank mates for bettas

All betta tank mates

Better tank mates for mollies

All molly tank mates

Questions

Can bettas live with mollies?

Yes, with care. Bettas and mollies can share a tank, but watch one thing. Water chemistry is a squeeze. The only pH that suits both is around 7.5.

What temperature suits both bettas and mollies?

76–82 °F. Bettas need 76–82 °F, mollies need 72–82 °F.

What size tank do bettas and mollies need together?

At least 20 gal, set by the molly. Add space for each extra fish.