Costa's Tetra Tank Mates

• Agassiz's Corydoras✅ Compatible
  Peaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
  • Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • 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)
  • Both are peaceful; 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.
• Betta✅ Compatible
  Semi-aggressive · 6.5 cm · Easy care · 24–28 °C (75–82 °F)
  • Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Black Kuhli Loach✅ Compatible
  Peaceful · 8 cm · Easy care · 23–28 °C (73–82 °F)
  • Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Black Skirt Tetra✅ Compatible
  Semi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
  • Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
  • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Keep Black Skirt Tetra in a shoal of 6+ or it gets stressed and nippy.
• Blackline Rasbora✅ Compatible
  Peaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
  • Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Keep Blackline Rasbora in a shoal of 6+ or it gets stressed and nippy.
• Blood Red Tiger Pleco✅ Compatible
  Peaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
  • Both are peaceful; 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.
• Bolivian Ram✅ Compatible
  Peaceful · 8 cm · Medium care · 24–28 °C (75–82 °F)
  • Both are peaceful; 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.
• Butterfly Hillstream Loach✅ Compatible
  Peaceful · 6 cm · Hard care · 18–24 °C (64–75 °F)
  • Both are peaceful; 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.
• Celebes Rainbowfish✅ Compatible
  Peaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
  • Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • 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)
  • Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Keep Corydoras Catfish in a shoal of 6+ or it gets stressed and nippy.
• Croaking Gourami✅ Compatible
  Peaceful · 7 cm · Easy care · 24–28 °C (75–82 °F)
  • Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Desert Goby✅ Compatible
  Semi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
  • Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Diamond Tetra✅ Compatible
  Peaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
  • Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
• Eastern Betta✅ Compatible
  Semi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
  • Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Keep Costa's Tetra 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)
  • Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Keep Elegant Cory in a shoal of 6+ or it gets stressed and nippy.
• Gold Barb✅ Compatible
  Peaceful · 7.5 cm · Easy care · 18–26 °C (64–79 °F)
  • Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
  • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Keep Gold Barb 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)
  • Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
  • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Peppered Corydoras✅ Compatible
  Peaceful · 7 cm · Easy care · 18–26 °C (64–79 °F)
  • Both are peaceful; 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.
  • 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)
  • Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Splashing Tetra✅ Compatible
  Peaceful · 8 cm · Medium care · 22–28 °C (72–82 °F)
  • Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Keep Splashing Tetra 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)
  • Both are peaceful; 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.
  • 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)
  • Both are peaceful, and their water overlaps around 22–27 °C — no size, zone or temperament conflicts.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • 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)
  • Both are peaceful; 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.
  • Keep Sterbai Corydoras in a shoal of 6+ or it gets stressed and nippy.
• African Butterfly Cichlid⚠️ With caution
  Semi-aggressive · 8 cm · Medium care · 22–28 °C (72–82 °F)
  • African Butterfly Cichlid is semi-aggressive and may chase or nip the smaller Costa's Tetra — plant heavily and break up sight lines.
  • Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Amazon Puffer⚠️ With caution
  Peaceful · 8 cm · Medium care · 23–28 °C (73–82 °F)
  • Your 75 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Keep Amazon Puffer 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)
  • Ash Lipped Apisto and Costa's Tetra are close in size, but the semi-aggressive one tends to dominate — add costa's tetra in a group to spread the pressure.
  • Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Banded Dwarf Cichlid⚠️ With caution
  Semi-aggressive · 7 cm · Medium care · 24–30 °C (75–86 °F)
  • Expect Banded Dwarf Cichlid to harass Costa's Tetra at times; give dense cover and watch them at feeding.
  • Keep Costa's 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)
  • Bleeding Heart Tetra is semi-aggressive and may chase or nip the smaller Costa's Tetra — plant heavily and break up sight lines.
  • Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • 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 Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • 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)
  • Buenos Aires Tetra is semi-aggressive and may chase or nip the smaller Costa's Tetra — plant heavily and break up sight lines.
  • Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • 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)
  • Your 75 L tank is below the ~114 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Keep Colombian Tetra in a shoal of 6+ or it gets stressed and nippy.
• Hongsloi Dwarf Cichlid⚠️ With caution
  Semi-aggressive · 7 cm · Medium care · 24–29 °C (75–84 °F)
  • Hongsloi Dwarf Cichlid is semi-aggressive and may chase or nip the smaller Costa's Tetra — plant heavily and break up sight lines.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Mahachai Betta⚠️ With caution
  Aggressive · 7 cm · Medium care · 24–30 °C (75–86 °F)
  • Expect Mahachai Betta to harass Costa's Tetra at times; give dense cover and watch them at feeding.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• 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 Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • 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 Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • 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)
  • Expect Roundtail Paradise Fish to harass Costa's Tetra at times; give dense cover and watch them at feeding.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Sumo Loach⚠️ With caution
  Semi-aggressive · 7 cm · Medium care · 22–26 °C (72–79 °F)
  • Sumo Loach and Costa's Tetra are close in size, but the semi-aggressive one tends to dominate — add costa's tetra in a group to spread the pressure.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Tiger Barb⚠️ With caution
  Semi-aggressive · 7 cm · Easy care · 22–28 °C (72–82 °F)
  • Tiger Barb and Costa's Tetra are close in size, but the semi-aggressive one tends to dominate — add costa's tetra in a group to spread the pressure.
  • Your 75 L tank is below the ~95 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
  • 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)
  • Umbrella Dwarf Cichlid is semi-aggressive and may chase or nip the smaller Costa's Tetra — plant heavily and break up sight lines.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Alligator Gar⛔ Not recommended
  Aggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
  • Size gap is too large (250 vs 7 cm): Alligator Gar will treat Costa's Tetra as food.
  • Alligator Gar clearly outsizes Costa's Tetra and is aggressive; risky unless the tank is big and well-planted.
  • Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Clown Knifefish⛔ Not recommended
  Aggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
  • Clown Knifefish (90 cm) is big enough to swallow the 7 cm Costa's Tetra whole.
  • Clown Knifefish is aggressive and may chase or nip the smaller Costa's Tetra — plant heavily and break up sight lines.
  • Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Fire Eel⛔ Not recommended
  Semi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
  • Costa's Tetra is bite-sized to a 100 cm predatory fire eel — it will be eaten.
  • Expect Fire Eel to harass Costa's Tetra at times; give dense cover and watch them at feeding.
  • Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Koi⛔ Not recommended
  Peaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
  • Size gap is too large (90 vs 7 cm): Koi will treat Costa's Tetra as food.
  • Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Redtail Catfish⛔ Not recommended
  Aggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
  • Redtail Catfish (120 cm) is big enough to swallow the 7 cm Costa's Tetra whole.
  • Expect Redtail Catfish to harass Costa's Tetra at times; give dense cover and watch them at feeding.
  • Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Spotted Gar⛔ Not recommended
  Aggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
  • Costa's Tetra is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
  • Expect Spotted Gar to harass Costa's Tetra at times; give dense cover and watch them at feeding.
  • Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Wels Catfish⛔ Not recommended
  Aggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
  • Costa's Tetra is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
  • Wels Catfish clearly outsizes Costa's Tetra and is aggressive; risky unless the tank is big and well-planted.
  • Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
• Wolf Cichlid⛔ Not recommended
  Aggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
  • Wolf Cichlid (72 cm) is big enough to swallow the 7 cm Costa's Tetra whole.
  • Expect Wolf Cichlid to harass Costa's Tetra at times; give dense cover and watch them at feeding.
  • Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
  • Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.

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.