Can bettas live with siamese algae eaters?

Verdict
Yes

Yes, bettas and siamese algae eaters can live together. Both are fine at 76–79°F. Plan on at least 30 gal.

BettaBetta76–82°F · pH 6.5–7.5 Siamese algae eaterSiamese algae eater75–79°F · pH 6.5–7.5

Why it works

Water side by side

55°60°65°70°75°80°85°90°Both: 76–79°Betta 76–82°Siamese algae eater 75–79°
The green band is the temperature range both can live in.
456789Both: 6.5–7.5Betta 6.5–7.5Siamese algae eater 6.5–7.5
The green band is the pH both tolerate.

Size to scale

Betta · 2.5 inSiamese algae eater · 6 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

BettaSiamese algae eater
Temperature76–82 °F75–79 °F
pH6.5–7.56.5–7.5
Adult size2.5 in6.0 in
Minimum tank5 gal30 gal
TemperamentSemi-aggressivePeaceful
Swims atTopBottom
GroupOne per tankAlone or in pairs
DietCarnivoreHerbivore

Better tank mates for bettas

All betta tank mates

Better tank mates for siamese algae eaters

All siamese algae eater tank mates

Questions

Can bettas live with siamese algae eaters?

Yes, bettas and siamese algae eaters can live together. Both are fine at 76–79°F. Plan on at least 30 gal.

What temperature suits both bettas and siamese algae eaters?

76–79 °F. Bettas need 76–82 °F, siamese algae eaters need 75–79 °F.

What size tank do bettas and siamese algae eaters need together?

At least 30 gal, set by the siamese algae eater. Add space for each extra fish.