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Bettas are sold in small cups on store shelves, which suggests they need almost nothing. That display is a holding arrangement, not a home. A betta kept properly is a curious, active fish that can live for years.
Key figures
- 2.5 gallons PetMD minimum aquarium volume for bettas
- 76 to 81°F PetMD water temperature range for bettas
- 15 to 25 percent PetMD weekly betta partial water change
The basic setup
PetMD’s betta care sheet lists what a betta needs:
| Need | PetMD guidance |
|---|---|
| Tank size | At least 2.5 gallons; 5 to 10 gallons is ideal |
| Temperature | 76 to 81°F |
| Heater | About 3 to 5 watts per gallon, checked with a thermometer |
| Filter | Low or adjustable flow |
| pH | Near 7 is ideal; 6.5 to 7.8 is fine |
| Lid | Yes, bettas can jump |
Why the heater matters
Bettas are tropical fish. PetMD notes that even if your home is usually in the safe range, a heater prevents temperature swings, which are very stressful to fish. A cold betta becomes sluggish and more prone to illness.
Weekly care
- Test the water for ammonia, nitrite, nitrate and pH.
- Siphon the gravel with a gravel vacuum.
- Change 15 to 25 percent of the water with treated water.
- Feed a high-protein food made for bettas, in small amounts.
Male bettas fight, which is why they are called Siamese fighting fish. Never house two males together.
The aquarium test-kit guide explains the readings behind water management. The tank placement guide covers a stable location for the equipment and routine access.
Questions people ask
What size tank does a betta need?
PetMD recommends at least 2.5 gallons, with 5 to 10 gallons ideal for more stable water.
Do betta fish need a heater?
Yes. They need water between 76 and 81°F, and a heater prevents stressful swings.
Can bettas live in a bowl or vase?
Not well. Small unheated containers cannot hold a stable temperature or water quality.
Can two bettas live together?
Two males will fight. Keep one male per tank.
Where these figures come from
- Betta Fish Care Sheet PetMD · petmd.com
Figures last checked September 2026.
