Here’s detailed advice on betta fish tank sizes, synthesized from multiple sources:
I. Basic Size Requirements
Minimum Size for Single Keeping
Chinese Betta: Recommended 20×20×25cm (L×W×H) square tank.
Siamese Betta: At least 15×15×15cm square tank; 20×20×20cm is preferred.
Note: 10cm tanks are not recommended due to insufficient space, which easily causes injuries from collisions or jumping out.
Volume Conversion
Minimum effective water volume: 5L for Chinese bettas, 3L for Siamese bettas.
Comfortable volume: 20–40cm tanks with 10–30L water provide more stable conditions.
II. Advanced Selection Tips
Group Keeping Needs
For mixing multiple Chinese bettas, a 60×60×60cm square tank (accommodating ~20–30 fish) is required.
Breeding - Dedicated Tanks
Suggest 25×25×30cm with a lid to prevent jumping.
III. Shape and Material
Preferred Choices
Ultra - white glass square tanks (excellent light transmission for easy observation).
Avoid circular/irregular tanks (which can cause stress to fish).
Special Designs
Lidded tanks (bettas are prone to jumping).
Tanks with dark substrate (enhances bettas’ color expression).
IV. Common Misconceptions
"Small containers are acceptable"
Long - term use of <15cm tanks reduces bettas’ vitality and shortens their lifespan.
Impact of Scenery
Decorations reduce effective water volume; deduct 2L for every 1kg of driftwood.