Betta Tank Mates

Betta is semi-aggressive, so its tank mates need choosing with care. Here are the 49 freshwater species that pair well with a betta — plus the 102 to avoid — with a live checker you can tune to your own tank.

By The Aquarium DB Team • Updated June 7, 2026 • Full Betta care guide →
Best matches

The best tank mates for a betta

  • Assassin Snail ✅ Compatible
    Easy care · Peaceful · 3 cm · 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.
  • Malaysian Trumpet Snail ✅ Compatible
    Easy care · Peaceful · 3 cm · 21–27 °C (70–81 °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.
  • Axelrod's Cory ✅ Compatible
    Easy care · Peaceful · 5 cm · 23–28 °C (73–82 °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.
  • Bandit Corydoras ✅ Compatible
    Easy care · Peaceful · 5 cm · 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.
  • Japanese Trapdoor Snail ✅ Compatible
    Easy care · Peaceful · 5 cm · 10–28 °C (50–82 °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.
  • Julii Corydoras ✅ Compatible
    Easy care · Peaceful · 5 cm · 23–26 °C (73–79 °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.
  • Masked Corydoras ✅ Compatible
    Easy care · Peaceful · 5 cm · 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.
  • Skunk Corydoras ✅ Compatible
    Easy care · Peaceful · 5 cm · 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.
  • Rust Corydoras ✅ Compatible
    Easy care · Peaceful · 5.5 cm · 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.
  • Agassiz's Corydoras ✅ Compatible
    Easy care · Peaceful · 6 cm · 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.
  • Elegant Cory ✅ Compatible
    Easy care · Peaceful · 6 cm · 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.
  • False Julii Corydoras ✅ Compatible
    Easy care · Peaceful · 6 cm · 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.
  • Corydoras Catfish ✅ Compatible
    Easy care · Peaceful · 6.5 cm · 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.
  • Spotfin Corydoras ✅ Compatible
    Easy care · Peaceful · 6.5 cm · 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.
  • Costa's Tetra ✅ Compatible
    Easy care · Peaceful · 7 cm · 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.
  • Peppered Corydoras ✅ Compatible
    Easy care · Peaceful · 7 cm · 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.
  • Spotted Corydoras ✅ Compatible
    Easy care · Peaceful · 7 cm · 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.
  • Gold Barb ✅ Compatible
    Easy care · Peaceful · 7.5 cm · 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.
  • Black Kuhli Loach ✅ Compatible
    Easy care · Peaceful · 8 cm · 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.
  • Brilliant Rasbora ✅ Compatible
    Easy care · Peaceful · 9 cm · 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.
  • Burmese Loach ✅ Compatible
    Easy care · Peaceful · 9 cm · 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.
  • Kuhli Loach ✅ Compatible
    Easy care · Peaceful · 10 cm · 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.
  • Molly ✅ Compatible
    Easy care · Peaceful · 10 cm · 23–28 °C (73–82 °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.
  • Murray River Rainbowfish ✅ Compatible
    Easy care · Peaceful · 11 cm · 15–26 °C (59–79 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–26 °C — no size, zone or temperament conflicts.
With caution

Betta tank mates that can work with care

  • Afra Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 10 cm · 24–28 °C (75–82 °F)
    pH preferences only just meet (Betta 6–7.5 vs Afra Cichlid 7.8–8.6) — target the overlap and acclimate slowly.
  • African Butterfly Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 8 cm · 22–28 °C (72–82 °F)
    Betta and African Butterfly Cichlid can both be territorial; doable with space and dense planting, but watch for chasing.
  • African Dwarf Frog ⚠️ With caution
    Medium care · Peaceful · 4 cm · 22–26 °C (72–79 °F)
    African Dwarf Frog is small enough to tempt Betta; only risk it in a densely planted setup with hiding spots.
  • Agassiz's Dwarf Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 9 cm · 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.
  • Amano Shrimp ⚠️ With caution
    Easy care · Peaceful · 5 cm · 18–28 °C (64–82 °F)
    Adult Amano Shrimp might survive with Betta, but expect the young to be eaten — plant heavily.
  • Amapá Tetra ⚠️ With caution
    Medium care · Peaceful · 4 cm · 24–27 °C (75–81 °F)
    Betta clearly outsizes Amapá Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
  • Amazon Puffer ⚠️ With caution
    Medium care · Peaceful · 8 cm · 23–28 °C (73–82 °F)
    Your 75 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
  • Angelfish ⚠️ With caution
    Medium care · Semi-aggressive · 15 cm · 24–30 °C (75–86 °F)
    Betta and Angelfish can both be territorial; doable with space and dense planting, but watch for chasing.

+ 181 more “with caution” pairings — see the interactive checker above.

Avoid

Fish to avoid keeping with a betta

  • Wels Catfish ⛔ Avoid
    Hard care · Aggressive · 300 cm · 15–25 °C (59–77 °F)
    Betta and Wels Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
  • Alligator Gar ⛔ Avoid
    Hard care · Aggressive · 250 cm · 24–28 °C (75–82 °F)
    Betta and Alligator Gar are both territorial and at least one is outright aggressive — expect serious fighting.
  • Redtail Catfish ⛔ Avoid
    Hard care · Aggressive · 120 cm · 24–27 °C (75–81 °F)
    Betta and Redtail Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
  • Fire Eel ⛔ Avoid
    Medium care · Semi-aggressive · 100 cm · 24–28 °C (75–82 °F)
    Betta is bite-sized to a 100 cm predatory fire eel — it will be eaten.
  • Clown Knifefish ⛔ Avoid
    Hard care · Aggressive · 90 cm · 24–28 °C (75–82 °F)
    Two assertive fish, one genuinely aggressive: Betta and Clown Knifefish will hold territory and clash.
  • Koi ⛔ Avoid
    Medium care · Peaceful · 90 cm · 4–28 °C (39–82 °F)
    Size gap is too large (90 vs 6.5 cm): Koi will treat Betta as food.
  • Spotted Gar ⛔ Avoid
    Hard care · Aggressive · 90 cm · 18–26 °C (64–79 °F)
    Betta and Spotted Gar are both territorial and at least one is outright aggressive — expect serious fighting.
  • Wolf Cichlid ⛔ Avoid
    Hard care · Aggressive · 72 cm · 24–30 °C (75–86 °F)
    Two assertive fish, one genuinely aggressive: Betta and Wolf Cichlid will hold territory and clash.

+ 94 more to avoid — the checker above flags every one.

Interactive tool

Check any fish against a betta

Dial in your exact tank size and filter by result — the checker scores every species in our database against a betta, with the reasoning for each verdict.

Tank-mate checker

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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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✅ Compatible
    Peaceful · 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 caution
    Semi-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 caution
    Semi-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 caution
    Semi-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 caution
    Semi-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 caution
    Semi-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 caution
    Peaceful · 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 caution
    Semi-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 caution
    Semi-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 caution
    Peaceful · 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 caution
    Semi-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 caution
    Peaceful · 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 caution
    Peaceful · 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 caution
    Semi-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 caution
    Semi-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 caution
    Semi-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 caution
    Semi-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 recommended
    Aggressive · 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 recommended
    Aggressive · 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 recommended
    Semi-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 recommended
    Peaceful · 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 recommended
    Aggressive · 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 recommended
    Aggressive · 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 recommended
    Aggressive · 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 recommended
    Aggressive · 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.

Setting up a betta community tank

Give the group a stable, planted 75 L+ tank with a gentle filter, a reliable heater and plenty of cover — broken sight lines and hiding spots let mid-water and bottom dwellers keep out of each other's way. Cycle it fully and stock gradually.

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How to choose

How to choose the right tank mates for a betta

Being semi-aggressive, betta can nip or harass smaller, slower or long-finned fish — give it space, broken sight-lines and similarly robust companions. It mostly occupies the top of the tank, so it pairs naturally with species that use the other levels.

Betta grows to about 6.5 cm, so avoid tank mates small enough to be seen as food — as a rule of thumb, skip anything under roughly 3 cm. Match its water, too: aim for 24–28 °C (75–82 °F), pH 6–7.5 and 3–10 dGH. Fish needing very different conditions — coldwater species, or hard-water lovers against a soft-water fish — rarely thrive side by side.

Betta doesn't need its own kind to feel secure; think twice before keeping more than one if it is territorial. Whatever you add, introduce new fish slowly, watch for bullying in the first days, and have a backup plan if temperaments clash.

FAQ

Frequently asked questions

Can a betta live with other fish?

Yes — with the right companions. Our checker finds 49 compatible freshwater species for betta. Pick calm, similarly-sized fish that share its water needs and add them to a mature, well-planted tank.

What is the best tank mate for a betta?

Easy, peaceful, similarly-sized species top the list — for example Assassin Snail, Malaysian Trumpet Snail, Axelrod's Cory. Use the checker above to match against your own tank size.

What fish should you avoid keeping with a betta?

Avoid Wels Catfish, Alligator Gar, Redtail Catfish and similar — usually a temperature, size or temperament clash. The full "avoid" list below gives the reason for each.

How big a tank do betta tank mates need?

Start from Betta's own minimum and scale up with every addition. The checker above defaults to a 75 L community tank and flags pairings that need more room — drag the slider to match your setup.

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