Betta fish
Betta splendens · family Osphronemidae
The betta fish (Betta splendens) is a small, long-finned freshwater fish from mainland Southeast Asia, reaching about 2.5–2.8 inches as an adult. It's easy to care for, but it needs a heated, filtered tank of at least 5 gallons, not a bowl. The most important thing to know is that bettas live one to a tank, and two males will fight, often fatally.
Edited by Marin Hale · last reviewed October 29, 2026 · How we check facts
Great for beginnersTropicalMature tank onlyNano tank OK
What can live with a betta fish?
Verdicts against every species in our database, from our compatibility rules. How verdicts work
Full guide: betta tank mates by tank size →
| Verdict | Species | Why | Tank |
|---|---|---|---|
| Good match | Ember tetra | No problems found: water, size, fins and temperament all check out. | 10 gal+ |
| Good match | Pygmy corydoras | No problems found: water, size, fins and temperament all check out. | 10 gal+ |
| Maybe | Cherry shrimp | Betta fish eat baby shrimp and may pick off adults. Dense plants and moss help a colony survive. | 5 gal+ |
| Maybe | Guppy | Male guppies' long, colorful tails look like a rival betta and often trigger attacks, and guppies may nip back. Female guppies in a 20+ gallon planted tank work best. | 20 gal+ |
| Maybe | Neon tetra | Usually fine with a group of 6+ neons, but stressed neons can nip and some bettas chase them. | 20 gal+ |
| Maybe | Zebra nerite snail | pH ranges only just overlap (7.2–7.5), so one of them will be outside its comfort zone if your water drifts. | 5 gal+ |
| Avoid | Angelfish | Angelfish grow far larger and are territorial, both claim the upper water, and each has long fins the other may attack. | — |
| Avoid | Another betta fish | Two male bettas fight, often until one dies. Keeping groups of females ("sororities") is now widely discouraged too, because fights and stress are common. | — |
| Avoid | Common goldfish | Common goldfish need cool water; betta fish need tropical water. | — |
| Avoid | Fancy goldfish | Fancy goldfish need cool water; betta fish need tropical water. | — |
| Avoid | Tiger barb | Tiger barbs nip fins, and betta fish have long fins. | — |
Setup and care
| Heater | Yes. Set an adjustable heater to 75–79°F (24–26°C); betta fish tolerate 75–82°F, and most rooms are cooler than that. |
|---|---|
| Feeding | Dried foods plus regular small live or frozen foods (Daphnia, Artemia, bloodworm); avoid overfeeding |
| New tanks | Add only to an established, cycled tank. Not for a brand-new setup. |
| Males vs females | Females have an ovipositor tube used for egg delivery |
| Male:female ratio | One betta per tank. Never keep two males together, and female groups (sororities) are no longer recommended. |
| Breeding | After spawning the female is chased away and may be killed by the male if not removed |
Watch out for
- Males kept together fight, often fatally
- Females can also become territorial in confined spaces
- Tolerant of low oxygen and poor water quality due to labyrinth organ
- Excellent jumper, keep tank well covered
- Needs access to humid air layer above water, do not fill to top
- Avoid strong water movement
Care tips
- Keep your betta in a heated, filtered tank of at least 5 gallons, with the temperature between 75–82°F and ideally 75–79°F.
- Choose a filter with low flow, because strong currents and water movement are hard on their frail fins.
- Use a tight lid, since bettas are excellent jumpers, and don't fill the tank to the top, because they need access to the humid air layer above the water.
- Feed small portions and remove any uneaten food, since bettas are prone to obesity and overfeeding harms water quality.
Questions
Do betta fish need a heater?
Yes. Bettas tolerate 75–82°F, with 75–79°F ideal, and they need a heated, filtered tank rather than an unheated bowl.
What do betta fish eat?
Bettas are carnivores. Feed dried foods plus regular small live or frozen foods such as Daphnia, Artemia and bloodworm, and avoid overfeeding.
What fish can live with betta fish?
Ember tetras and pygmy corydoras are the best matches, with no problems found. Neon tetras (in a group of 6+), female guppies (in a planted tank of 20+ gallons), cherry shrimp and zebra nerite snails all call for caution. Angelfish, goldfish, tiger barbs and other bettas are a no.
Can you keep more than one betta together?
No. Keep one betta per tank. Males kept together fight, often fatally, and female groups (sororities) are no longer recommended. Females can also become territorial in confined spaces.
How long do betta fish live?
Bettas typically live 3–5 years. Tiny bowls shorten that to 18 months–2 years, so a heated, filtered tank gives your fish the best chance of a full life.
Sources
Each value is cross-checked across the references below. Where they disagreed, an editor chose a value and recorded why.
- Siamese fighting fish (en.wikipedia.org)
- Betta splendens (Seriously Fish) (www.seriouslyfish.com)
- Keeping a Better Betta Fish Aquarium (www.tfhmagazine.com)
- Keeping Bettas: How to Care for a Betta Fish (buceplant.com)
- 7 Betta Fish Facts: Lifespan, Size & Care (www.petmd.com)
- GBIF taxonomy record
- Wikidata entry
Where each value comes from (21 facts)
| Fact | What each source says |
|---|---|
| Adult size | en.wikipedia.org: “B. splendens usually grows to a length of about 6–8 cm (2.4–3.1 in).” seriouslyfish.com: “Max size 70mm SL2.8in SL” petmd.com: “Most betta fish will reach about 2.5 inches long as adults, not including their tails.” |
| Temperament editor decision | en.wikipedia.org: “Bettas are well known for being highly territorial, with males frequently engaging in aggressive interactions when kept together” seriouslyfish.com: “Ornamental strains seem to be more aggressive than any other Betta species” buceplant.com: “the males of this species are known for picking fights with other bettas, or similarly sized fish, and are extremely territorial.” petmd.com: “Male bettas should never be housed together, as they will often fight, sometimes fatally.” |
| Long fins | en.wikipedia.org: “Although aquarium specimens are widely known for their brilliant colors and large, flowing fins” seriouslyfish.com: “Males are more colourful and develop more-extended fins than females” tfhmagazine.com: “It is even worse for males of ornamental strains that have extra-long finnage.” petmd.com: “Some have long, flowing fins, while others have shorter, more compact tails.” |
| Diet | en.wikipedia.org: “Betta splendens is naturally carnivorous, feeding on zooplankton, small crustaceans, and the larvae of aquatic insects” seriouslyfish.com: “Likely to prey on aquatic and terrestrial invertebrates in nature.” tfhmagazine.com: “the bettas are powerfully carnivorous, their native fare being fish fry, crustaceans, insect larvae, and minuscule worms.” buceplant.com: “Bettas are carnivores, so they require a diet that is rich in protein.” petmd.com: “Bettas are carnivores so their diet should be high in protein.” |
| Water type | en.wikipedia.org: “is a freshwater fish native to Mainland Southeast Asia” seriouslyfish.com: “The Siamese fighting fish, Betta splendens, is a labyrinth fish from central Thailand, native to rice paddies, swamps, ditches and other still waters.” buceplant.com: “Betta splendens, are bred in captivity all around the world” petmd.com: “Bettas are freshwater fish, and they generally live in shallow areas like rice paddies and marshes.” |
| Breeding type | en.wikipedia.org: “Males build bubble nests of various sizes and thicknesses at the surface of the water” seriouslyfish.com: “Bubble nester.” |
| Native to | en.wikipedia.org: “native to Mainland Southeast Asia, namely Cambodia, Laos, Myanmar, Malaysia, Thailand, and Vietnam” seriouslyfish.com: “Occurs naturally throughout central Thailand” tfhmagazine.com: “Hailing from the warm, oxygen-poor waters of Thailand, Burma, and surrounding areas” petmd.com: “Bettas originally come from Southeast Asia and can be found in:” |
| Telling males from females | en.wikipedia.org: “one way to distinguish between the two is to identify the ovipositor tube that's located in females used for egg delivery.” seriouslyfish.com: “Males are more colourful and develop more-extended fins than females” |
| Breeding | en.wikipedia.org: “If she is not removed from the tank, she would likely be killed by the male.” seriouslyfish.com: “the adults do not usually eat their offspring.” |
| Temperature editor decision | seriouslyfish.com: “Temperature: 22 – 30 °C72 – 86 °F” tfhmagazine.com: “Aquaria should be heated to between 74° and 79°F for optimal comfort and metabolic efficiency.” buceplant.com: “should be kept at a temperature of 75F-80F.” |
| pH editor decision | seriouslyfish.com: “ornamental strains are unfussy with a range of 6.0 – 8.0 acceptable.” buceplant.com: “They are able to tolerate low water flow with a pH of 6.5-7.5.” |
| Smallest tank editor decision | seriouslyfish.com: “An aquarium with base measurements of 45 ∗ 30 cm18 ∗ 12 in or equivalent is large enough for a single male or pair.” buceplant.com: “A betta tank should be a minimum of 3 gallons at the very least.” petmd.com: “The ideal tank size for a betta is at least 10 gallons, though larger tanks provide more space and enrichment.” |
| Group size | seriouslyfish.com: “Its care requirements and disposition mean it is best kept alone.” buceplant.com: “if you plan on keeping a male betta, then it's recommended to keep that male betta alone in your aquarium.” petmd.com: “Male bettas should be kept alone, while females can live together under the right conditions.” |
| Care level | seriouslyfish.com: “Difficulty6 of 8 measures Moderate” buceplant.com: “bettas are considered an exceptional starting fish for beginner hobbyists due to their hardiness and accessibility” petmd.com: “relatively easy care requirements, making them a great fish for beginners.” |
| Hardness (GH) | seriouslyfish.com: “Hardness: 1 – 15 dGH” buceplant.com: “Although they prefer soft water, Betta splendens will still do fine in moderately hard water.” |
| Feeding | seriouslyfish.com: “should be offered plenty of small live or frozen foods such as Daphnia, Artemia or chironomid larvae (bloodworm) regularly” tfhmagazine.com: “Avoid feeding regular fish flakes, spirulina, or other vegetative foods in favor of newly hatched brine shrimp” buceplant.com: “Only feed your betta 2-4 pellets or flakes once a day.” petmd.com: “Feed your betta once daily in small portions.” |
| Lifespan editor decision | tfhmagazine.com: “free-ranging specimens housed in larger aquaria may thrive for more than seven or eight years!” petmd.com: “Most bettas live three to five years, though some have been known to live up to 10 years with excellent care.” |
| Swims | tfhmagazine.com: “Because bettas favor the upper reaches of the water column” buceplant.com: “bettas tend to feed from the surface of the water and would generally be more territorial at the top of the water column.” |
| Eats shrimp/snails editor decision | buceplant.com: “although some bettas might consider shrimp a "snack," certain shrimp are common tank mates” |
| Mature tank only | buceplant.com: “First and foremost, make sure your tank is cycled prior to adding your betta.” |
| Male:female ratio editor decision | buceplant.com: “you should never keep more than one male betta in a single tank. Females, on the other hand, are able to coexist with one another.” petmd.com: “pet parents can keep three to five female bettas together. Females should be kept in odd numbers” |
Editor decisions (7)
- Sources call bettas aggressive, but that aggression is aimed at other bettas and long-finned fish. With small, calm, short-finned fish they're usually tolerant, which the hobby calls semi-aggressive.
- TFH gives 74–79°F, Buce Plant 75–80°F and Seriously Fish 72–86°F; 75–82°F is comfortable across all three.
- Seriously Fish 6.0–8.0, Buce Plant 6.5–7.5; bettas do best in slightly acidic to neutral water.
- 5 gallons is the widely accepted minimum for one betta (Buce Plant says 3); PetMD and Seriously Fish recommend about 10.
- PetMD's 3–5 years is typical; TFH's 7–8 years is a best case in large tanks.
- Buce Plant notes some bettas treat shrimp as a snack; consistent with the hobby view that bettas hunt small shrimp.
- Seriously Fish notes females can coexist, but most of the hobby now discourages sororities because fights and stress are common.