Photo: ErgoSum88 (Public domain) — via Wikimedia Commons
Betta (Betta splendens)
The jewel-finned loner of the aquarium world — stunning, hardy, and far more demanding than the bowl on the pet-store shelf suggests.
Will it live with a Betta?
We compare each fish against your betta on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Adolf's Cory✅ CompatiblePeaceful · 5.5 cm · Medium care · 22–26 °C (72–79 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–26 °C — no size, zone or temperament conflicts.
- Keep Adolf's Cory in a shoal of 6+ or it gets stressed and nippy.
- Agassiz's Corydoras✅ CompatiblePeaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Bamboo Shrimp✅ CompatiblePeaceful · 8 cm · Medium care · 22–27 °C (72–81 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–27 °C — no size, zone or temperament conflicts.
- Black Kuhli Loach✅ CompatiblePeaceful · 8 cm · Easy care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Blood Red Tiger Pleco✅ CompatiblePeaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Butterfly Hillstream Loach✅ CompatiblePeaceful · 6 cm · Hard care · 18–24 °C (64–75 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–24 °C — no size, zone or temperament conflicts.
- Celebes Rainbowfish✅ CompatiblePeaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Celebes Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Corydoras Catfish✅ CompatiblePeaceful · 6.5 cm · Easy care · 22–26 °C (72–79 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Corydoras Catfish in a shoal of 6+ or it gets stressed and nippy.
- Costa's Tetra✅ CompatiblePeaceful · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
- Duplicareus Corydoras✅ CompatiblePeaceful · 5.5 cm · Medium care · 23–27 °C (73–81 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Duplicareus Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Elegant Cory✅ CompatiblePeaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Elegant Cory in a shoal of 6+ or it gets stressed and nippy.
- False Julii Corydoras✅ CompatiblePeaceful · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–26 °C — no size, zone or temperament conflicts.
- Keep False Julii Corydoras in a shoal of 6+ or it gets stressed and nippy.
- German Blue Ram✅ CompatiblePeaceful · 6 cm · Hard care · 27–30 °C (81–86 °F)
- Compatible on the things that matter: shared water near 27–28 °C, workable temperaments, and no predator-and-prey size gap.
- Gold Barb✅ CompatiblePeaceful · 7.5 cm · Easy care · 18–26 °C (64–79 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Gold Barb in a shoal of 6+ or it gets stressed and nippy.
- Hillstream Loach✅ CompatiblePeaceful · 6 cm · Hard care · 20–24 °C (68–75 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Narcissus II Cory✅ CompatiblePeaceful · 5.5 cm · Medium care · 22–26 °C (72–79 °F)
- Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Narcissus II Cory in a shoal of 6+ or it gets stressed and nippy.
- Peacock Gudgeon✅ CompatiblePeaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Peppered Corydoras✅ CompatiblePeaceful · 7 cm · Easy care · 18–26 °C (64–79 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–26 °C — no size, zone or temperament conflicts.
- Keep Peppered Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Rio Negro Checkerboard Cichlid✅ CompatiblePeaceful · 7 cm · Hard care · 24–29 °C (75–84 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Rust Corydoras✅ CompatiblePeaceful · 5.5 cm · Easy care · 23–27 °C (73–81 °F)
- Compatible on the things that matter: shared water near 24–27 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Rust Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Slate Corydoras✅ CompatiblePeaceful · 6 cm · Medium care · 23–28 °C (73–82 °F)
- Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Slate Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Spotfin Corydoras✅ CompatiblePeaceful · 6.5 cm · Easy care · 22–26 °C (72–79 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Spotfin Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Spotted Corydoras✅ CompatiblePeaceful · 7 cm · Easy care · 22–27 °C (72–81 °F)
- Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Spotted Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Sterbai Corydoras✅ CompatiblePeaceful · 6.5 cm · Medium care · 24–30 °C (75–86 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Sterbai Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Ash Lipped Apisto⚠️ With cautionSemi-aggressive · 7 cm · Hard care · 24–29 °C (75–84 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Banded Dwarf Cichlid⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 24–30 °C (75–86 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Black Ruby Barb⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 22–26 °C (72–79 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Black Ruby Barb is a notorious fin-nipper — even though Betta is larger, an active shoal will harass its trailing fins. Only safe in a full group of 6+ with plenty of cover.
- Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
- Keep Black Ruby Barb in a shoal of 6+ or it gets stressed and nippy.
- Black Skirt Tetra⚠️ With cautionSemi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Black Skirt Tetra is a notorious fin-nipper — even though Betta is larger, an active shoal will harass its trailing fins. Only safe in a full group of 6+ with plenty of cover.
- Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bleeding Heart Tetra⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 23–28 °C (73–82 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Bleeding Heart Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bright Diamond Tetra⚠️ With cautionPeaceful · 7 cm · Hard care · 24–28 °C (75–82 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
- Buenos Aires Tetra⚠️ With cautionSemi-aggressive · 7 cm · Easy care · 18–26 °C (64–79 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Colombian Tetra⚠️ With cautionSemi-aggressive · 6.5 cm · Easy care · 24–28 °C (75–82 °F)
- Betta and Colombian Tetra can both be territorial; doable with space and dense planting, but watch for chasing.
- Your 75 L tank is below the ~114 L this pairing really wants — crowding raises aggression.
- Keep Colombian Tetra in a shoal of 6+ or it gets stressed and nippy.
- Croaking Gourami⚠️ With cautionPeaceful · 7 cm · Easy care · 24–28 °C (75–82 °F)
- Betta and Croaking Gourami are both labyrinth fish and often treat each other as rivals — give a large, broken-up tank and be ready to separate them.
- Hongsloi Dwarf Cichlid⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 24–29 °C (75–84 °F)
- Betta and Hongsloi Dwarf Cichlid can both be territorial; doable with space and dense planting, but watch for chasing.
- Melon Barb⚠️ With cautionPeaceful · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Melon Barb in a shoal of 8+ or it gets stressed and nippy.
- Rounded Filament Barb⚠️ With cautionPeaceful · 7 cm · Medium care · 22–27 °C (72–81 °F)
- Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
- Keep Rounded Filament Barb in a shoal of 6+ or it gets stressed and nippy.
- Roundtail Paradise Fish⚠️ With cautionSemi-aggressive · 7 cm · Easy care · 10–26 °C (50–79 °F)
- Betta and Roundtail Paradise Fish can both be territorial; doable with space and dense planting, but watch for chasing.
- Betta and Roundtail Paradise Fish are both labyrinth fish and often treat each other as rivals — give a large, broken-up tank and be ready to separate them.
- Sumo Loach⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 22–26 °C (72–79 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Tiger Barb⚠️ With cautionSemi-aggressive · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Betta and Tiger Barb can both be territorial; doable with space and dense planting, but watch for chasing.
- Your 75 L tank is below the ~95 L this pairing really wants — crowding raises aggression.
- Keep Tiger Barb in a shoal of 6+ or it gets stressed and nippy.
- Umbrella Dwarf Cichlid⚠️ With cautionSemi-aggressive · 7 cm · Medium care · 20–26 °C (68–79 °F)
- Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
- Alligator Gar⛔ Not recommendedAggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
- Betta and Alligator Gar are both territorial and at least one is outright aggressive — expect serious fighting.
- Alligator Gar (250 cm) is big enough to swallow the 6.5 cm Betta whole.
- Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Clown Knifefish⛔ Not recommendedAggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
- Two assertive fish, one genuinely aggressive: Betta and Clown Knifefish will hold territory and clash.
- Size gap is too large (90 vs 6.5 cm): Clown Knifefish will treat Betta as food.
- Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Fire Eel⛔ Not recommendedSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Betta is bite-sized to a 100 cm predatory fire eel — it will be eaten.
- Betta and Fire Eel can both be territorial; doable with space and dense planting, but watch for chasing.
- Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Size gap is too large (90 vs 6.5 cm): Koi will treat Betta as food.
- Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Betta and Redtail Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
- Size gap is too large (120 vs 6.5 cm): Redtail Catfish will treat Betta as food.
- Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Betta and Spotted Gar are both territorial and at least one is outright aggressive — expect serious fighting.
- Betta is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
- Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Betta and Wels Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
- Size gap is too large (300 vs 6.5 cm): Wels Catfish will treat Betta as food.
- Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Two assertive fish, one genuinely aggressive: Betta and Wolf Cichlid will hold territory and clash.
- Size gap is too large (72 vs 6.5 cm): Wolf Cichlid will treat Betta as food.
- Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Betta care specs
- Care level
- Easy
- Breeding
- Medium
- Max size
- 6.5 cm (2.6 in)
- Min tank size
- 19 L (5 gal)
- Temperature
- 24–28 °C (75–82 °F)
- pH
- 6–7.5
- Hardness
- 3–10 dGH
- Lifespan
- 3–5 years
- Diet
- Carnivore
- Swim level
- Top
- Group size
- Best alone or in a pair
- Family
- Osphronemidae
- Origin
- Mekong basin — Thailand, Cambodia, Vietnam, Laos
What is a betta fish?
The betta (Betta splendens), or Siamese fighting fish, is one of the most recognisable freshwater aquarium fish in the world — and one of the most misunderstood. Males trail extravagant fins in almost every colour a breeder can coax out of them, which is exactly why they end up in tiny cups and decorative bowls. In reality the betta is a tropical fish with the same needs as any other: warm, clean, stable water and room to swim.
Bettas belong to a group called labyrinth fish. A special organ lets them gulp air from the surface, so they survive in the warm, low-oxygen, slow-moving water of their native range. That toughness is real, but it is not a licence to keep them in an unheated bowl — it is the trait that lets a well-kept betta thrive.
Where do betta fish come from?
Wild bettas live in the Mekong basin across Thailand, Cambodia, Vietnam and Laos, in rice paddies, floodplains, slow streams and roadside ditches. This water is warm, soft, slightly acidic and densely planted. Understanding that origin explains everything about good betta care: they want heat, gentle flow, soft-to-neutral water and plenty of cover to feel secure.
The fish in stores are many generations removed from wild Betta splendens — selectively bred for fin shape and colour rather than the drab, short-finned wild type. The care, however, is the same.
What size tank does a betta need?
The honest minimum is 19 litres (5 gallons), heated and filtered. Bigger is genuinely easier: more water dilutes waste and holds temperature steady, so a 19–40 L planted tank is far more forgiving than a 2 L bowl that swings cold and dirty overnight.
Bettas are surface-oriented and need to reach the top to breathe, so choose a tank that is longer than it is tall and keep the current gentle — those long fins are easily battered by a strong filter. Add a lid: bettas are accomplished jumpers.
What water parameters do bettas need?
- Temperature: 24–28 °C (75–82 °F) — a heater is non-negotiable.
- pH: 6.0–7.5, soft to neutral.
- Hardness: 3–10 dGH.
Stability matters more than chasing perfect numbers. Cycle the tank before adding the fish, keep up with weekly water changes, and avoid sudden swings — most “betta is mysteriously sick” stories trace back to cold, uncycled or neglected water.
What do betta fish eat?
Bettas are carnivores built to eat insects and larvae at the surface. A staple of quality betta pellets, rotated with frozen or live bloodworms, daphnia and brine shrimp, keeps colour and energy up. Feed small amounts once or twice a day and skip a day each week — bettas beg constantly and overfeeding (plus the resulting waste) is a leading cause of bloat and foul water.
Are bettas aggressive — and what fish can live with them?
Bettas are semi-aggressive, and the aggression is mostly aimed at other bettas and at fish that resemble them — anything bright, long-finned or another surface-dweller invading their patch. Two males will fight; that is where the “fighting fish” name comes from.
That does not mean a betta must live alone. Many bettas share a 38 L+ planted community tank peacefully, as long as the tank-mates are calm, not fin-nippers, and ideally occupy a different zone of the tank. Peaceful bottom-dwellers like corydoras and kuhli loaches are classic companions; bright, flashy or nippy fish are the ones to avoid. Every betta has its own temperament, so add tank-mates slowly and watch.
For a full, filterable list of what works — and what doesn’t — see Betta tank mates, or test a specific pairing in the checker at the top of this page.
How do you tell a male from a female betta?
Sexing adult bettas is usually straightforward. Males are larger, with the long, flowing fins and saturated colour they’re famous for, and they flare readily. Females are smaller and shorter-finned, often less vivid, and show a small white egg spot (the ovipositor) between the ventral fins. Females also display a vertical “barring” pattern when ready to breed.
How do betta fish breed?
Bettas are bubble-nest builders with fascinating, hands-on breeding behaviour. The male builds a raft of bubbles at the surface; after a courtship display he wraps around the female in an “embrace,” fertilising eggs as they fall, then catches them and tucks them into the nest. He guards and tends the nest alone until the fry are free-swimming.
It is rewarding but not beginner-casual: it needs a dedicated breeding tank, conditioning, careful introductions to avoid injury, and a plan for raising dozens of fry on tiny live foods. We rate it medium difficulty.
What are common betta diseases?
The usual culprits are fin rot (ragged, receding fins — almost always a water-quality problem), ich (white spots), velvet (a dusty gold sheen), and swim-bladder issues / bloat from overfeeding or constipation. The overwhelming majority are prevented by the same things: a cycled tank, stable heat, weekly water changes and sensible feeding. Treat early, fix the water first, and quarantine new fish before they meet your betta.
Health note: medication dosing and disease diagnosis are beyond the scope of a care profile. For sick fish, confirm symptoms against a reputable veterinary or fish-health source before medicating.
How long do bettas live?
A well-kept betta lives 3–5 years. Because they’re usually sold as young adults, much of that clock may already have ticked by purchase. Give a betta a heated, filtered, planted tank and steady care and you’ll see the best of those years — and the full glory of those fins.
Frequently asked questions
Can two bettas live together?
No. Two males will fight, often to the death, and even females can be aggressive outside a carefully managed "sorority" in a large, heavily planted tank. Keep one male per tank.
What is the minimum tank size for a betta?
19 litres (5 gallons) is the practical minimum. The cups and bowls bettas are sold in are far too small — a heated, filtered 19 L+ tank keeps water stable and the fish healthy.
Do bettas need a heater?
Yes. Bettas are tropical and need a stable 24–28 °C (75–82 °F). Unheated tanks that swing cold leave them lethargic and prone to disease.
How big do bettas get?
About 6.5 cm (2.6 in) including the tail. Fancy long-finned forms look larger because of their finnage, not their body.
Can bettas live with other fish?
Often yes, with care. Peaceful, bottom-dwelling, drab tank-mates (like corydoras or kuhli loaches) in a 38 L+ planted tank are safest. Avoid bright, long-finned or nippy fish. Use the tank-mate checker above to test a specific pairing.
How long do bettas live?
Typically 3–5 years with good care. Because they're usually sold as adults, the clock is often already partway down by the time you buy one.
Why does my betta flare its gills?
Flaring is a territorial display — at its reflection, another fish, or you. Occasional flaring is healthy exercise; constant flaring is stressful, so remove the trigger.
What you need to keep a betta
The baseline is a heated, filtered 19 L+ tank: a reliable heater to hold 24–28 °C (75–82 °F), a gentle filter that won't batter a betta in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
As an Amazon Associate we earn from qualifying purchases — buying through these links costs you nothing extra.
