TankStocking

How many Betta (Siamese Fighting Fish) in a 5 gallon tank?

Keep exactly one Betta (Siamese Fighting Fish) in a 5-gallon tank — they must be housed alone or with non-rival tankmates.

By the TankStocking team · methodology-driven, sourced from aquarium care references Data v2026.06 · last reviewed How we judge this →

Betta (Siamese Fighting Fish) key facts

Key facts — Betta (Siamese Fighting Fish) (Betta splendens)
Adult size6.5 cm
Minimum tank5 US gal
Minimum group1 (keep singly)
TemperamentTerritorial
Temperature range24–28°C
pH range6–7.5
BioloadLow
Swim levelAll levels
Beginner-friendlyYes
Sources & confidence (1 species)

This backs the Betta (Siamese Fighting Fish) size, tank and group figures used here. Each figure is read from the TankStocking species database (v2026.06); below is the care reference behind it and how confident we are in that data. Confidence reflects the source quality, not whether any pairing is safe. Full source list and the welfare model are on the methodology page.

  • Betta (Siamese Fighting Fish) Betta splendens — Seriously Fish (seriouslyfish.com/species/betta-splendens) high confidence

Betta (Siamese Fighting Fish) is a keep-singly species: its own kind fight, often to the death, so the answer is always one regardless of tank size. A 5-gallon tank gives a single fish a good home with room for a careful clean-up crew. To add other species instead of more Betta (Siamese Fighting Fish), see the Betta (Siamese Fighting Fish) tank mates guide.

One Betta (Siamese Fighting Fish)

✓ Good starter plan

1× Betta (Siamese Fighting Fish)

A single Betta (Siamese Fighting Fish) is the only safe option — multiples fight, often fatally.

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      Common questions

      How many Betta (Siamese Fighting Fish) can I keep in a 5-gallon tank?

      Keep exactly one Betta (Siamese Fighting Fish) in a 5-gallon tank — they must be housed alone or with non-rival tankmates.

      What size tank do Betta (Siamese Fighting Fish) need?

      Betta (Siamese Fighting Fish) need at least 5 US gallons. Bigger is better — more water means more stable parameters and more room to stock tankmates.

      More on stocking Betta (Siamese Fighting Fish)

      Related guides on TankStocking — each scored by the same welfare engine as the planner.

      Betta (Siamese Fighting Fish) tankmates & community

      Betta (Siamese Fighting Fish) in other tank sizes

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      Stocking numbers are planning estimates — filtration, planting, and maintenance all shift the real ceiling. Cycle the tank and stock gradually. How this estimate works →