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Bettas, or Siamese fighting fish (Betta splendens), are among the most popular aquarium fish in the world. They're colourful, full of character and recognise their owners. They're also widely misunderstood: the idea that a betta is happy in a small bowl of unheated water is a myth. Given the right setup, a betta can live for three to five years or more.
Betta care at a glance
| Need | Recommendation |
|---|---|
| Tank size | 20 litres minimum; 30 litres or more is better |
| Temperature | 25–28°C, held steady with a heater |
| pH | 6.5‗7.5 |
| Filtration | Gentle flow; a sponge filter or adjustable nano filter |
| Diet | Carnivore: quality betta pellets plus frozen foods |
| Tankmates | Males alone, or with carefully chosen peaceful species |
| Lifespan | 3–5 years with good care |
Choosing the right tank
A larger volume of water is more stable, which means fewer swings in temperature and water quality. We recommend at least 20 litres for a single betta. A tank with a lid is essential, because bettas can jump.
- The Fluval Spec 19 Litre is a popular all-in-one with built-in filtration and LED lighting.
- The Aquael Shrimp Set Nano Aquarium is a compact, planted-tank-ready option that suits a betta well.
- For a little more space, the Fluval Flex 2.0 34L gives more room for plants and tankmates.
- Purpose-made kits such as the Fluval Betta Premium Aquarium Kit are designed around a betta's needs. See also our Aqua One Betta range.
Avoid bowls and vases. They're too small to keep stable, can't be heated safely and have no filtration.
Heating
Bettas are tropical fish from warm, shallow waters in Thailand and Cambodia. In a UK home, an unheated tank will usually sit around 18–21°C, which leaves a betta sluggish and vulnerable to disease. A small preset or adjustable heater solves this. The Sicce Jolly Heater Preset 25w is designed for small tanks, while the Fluval P25 lets you adjust the temperature. Browse all aquarium heaters.
Filtration and flow
Bettas need clean water, but their long fins make them weak swimmers and they tire in strong currents. Choose a gentle or adjustable filter, such as the EHEIM Nano Filter mini UP, or baffle the outlet of an all-in-one tank with a piece of sponge. If your betta is being pushed around or hides by the surface constantly, the flow is too strong. See our internal filters.
Before adding your betta, make sure the tank is cycled. Our guide on how to cycle your aquarium explains how.
Water and maintenance
- Change 20–25% of the water weekly, using a dechlorinator such as Seachem Prime and matching the temperature.
- Test ammonia, nitrite and nitrate regularly. Small tanks can change quickly.
- Bettas appreciate soft, slightly acidic water with tannins. Catappa leaves such as Hobby Catappa Leaves release tannins that tint the water a natural tea colour and mimic their wild habitat.
Decor and plants
Bettas like places to rest near the surface and somewhere to hide. Live plants with broad leaves, such as Anubias barteri, give natural resting spots. Floating plants dim the light and help them feel secure. Check that decor has no sharp edges that could tear delicate fins; if it would snag a pair of tights, it can snag a betta's fins. A planted substrate such as Fluval Betta Stratum supports plant growth and helps keep pH slightly soft. Browse our live aquarium plants.
Feeding
Bettas are carnivores and need a protein-rich diet. Feed a quality pellet such as Hikari Betta Bio-Gold once or twice a day, only as much as your betta eats in a minute or two, about two or three pellets. Supplement with frozen bloodworm, brine shrimp or daphnia a few times a week; see our frozen foods. Skipping one day a week helps digestion and prevents bloating. Overfeeding is the most common cause of constipation and poor water quality in betta tanks.
Tankmates
Male bettas must never be kept together; they'll fight, often to the death. Males and females should only be together for supervised breeding. Some bettas live peacefully with other species in a larger tank, but temperament varies from fish to fish.
- Usually suitable in 30 litres or more: nerite snails, small corydoras, kuhli loaches and some small rasboras.
- Avoid: fin-nippers such as tiger barbs, other labyrinth fish such as gouramis, and brightly coloured, long-finned fish such as fancy guppies that a betta may mistake for a rival.
- Shrimp are hit-and-miss. Some bettas ignore them; others treat them as food.
Our guide to fish you should never keep together has more detail.
Common betta health problems
- Fin rot: ragged, shrinking fins, usually caused by poor water quality. Improve water first; treat if it spreads.
- White spot and velvet: small white dots, or a gold dust, often after a temperature drop. See our white spot guide.
- Bloating and constipation: usually from overfeeding. Fast for a day or two.
- Lethargy: check the temperature first. A cold betta is an inactive betta.
What about bubble nests?
A male betta that builds a raft of bubbles at the surface is showing natural breeding behaviour. It's generally a sign that he's comfortable and healthy. You don't need to do anything; avoid disturbing it during water changes if you can.
Ready to set up? Browse our freshwater foods, heaters and nano aquariums, or ask our team for help choosing a setup for your betta.
