Can bettas live with boesemani rainbowfish?

Verdict
Yes

Yes. Bettas and boesemani rainbowfish make a good pair. Both are fine at 76–82°F. Plan on at least 30 gal.

BettaBetta76–82°F · pH 6.5–7.5 Boesemani rainbowfishBoesemani rainbowfish75–82°F · pH 7–8

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 76–82°Betta 76–82°Boesemani rainbowfish 75–82°
The green band is the temperature range both can live in.
456789Both: 7–7.5Betta 6.5–7.5Boesemani rainbowfish 7–8
The green band is the pH both tolerate.

Size to scale

Betta · 2.5 inBoesemani rainbowfish · 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

BettaBoesemani rainbowfish
Temperature76–82 °F75–82 °F
pH6.5–7.57–8
Adult size2.5 in4.0 in
Minimum tank5 gal30 gal
TemperamentSemi-aggressivePeaceful
Swims atTopMiddle
GroupOne per tankGroups of 6+
DietCarnivoreOmnivore

Better tank mates for bettas

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Better tank mates for boesemani rainbowfish

All boesemani rainbowfish tank mates

Questions

Can bettas live with boesemani rainbowfish?

Yes. Bettas and boesemani rainbowfish make a good pair. Both are fine at 76–82°F. Plan on at least 30 gal.

What temperature suits both bettas and boesemani rainbowfish?

76–82 °F. Bettas need 76–82 °F, boesemani rainbowfish need 75–82 °F.

What size tank do bettas and boesemani rainbowfish need together?

At least 30 gal, set by the boesemani rainbowfish. Add space for each extra fish.