Harlequin Rasbora Tank Mates

• Adolf's Cory✅ Compatible
  Peaceful · 5.5 cm · Medium care · 22–26 °C (72–79 °F)
  • Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Adolf's Cory in a shoal of 6+ or it gets stressed and nippy.
• Axelrod's Cory✅ Compatible
  Peaceful · 5 cm · Easy care · 23–28 °C (73–82 °F)
  • Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Axelrod's Cory in a shoal of 6+ or it gets stressed and nippy.
• Bandit Corydoras✅ Compatible
  Peaceful · 5 cm · Easy care · 22–27 °C (72–81 °F)
  • Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Bandit Corydoras in a shoal of 6+ or it gets stressed and nippy.
• Bloodfin Tetra✅ Compatible
  Peaceful · 5.5 cm · Easy care · 18–28 °C (64–82 °F)
  • Compatible on the things that matter: shared water near 23–28 °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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
• Checkered Barb✅ Compatible
  Peaceful · 5 cm · Easy care · 20–25 °C (68–77 °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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Checkered Barb in a shoal of 6+ or it gets stressed and nippy.
• Cherry Barb✅ Compatible
  Peaceful · 5 cm · Easy care · 23–27 °C (73–81 °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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Cherry Barb in a shoal of 6+ or it gets stressed and nippy.
• Chocolate Gourami✅ Compatible
  Peaceful · 5 cm · Hard care · 25–30 °C (77–86 °F)
  • Both are peaceful, and their water overlaps around 25–28 °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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Chocolate Gourami in a shoal of 6+ or it gets stressed and nippy.
• Cochu's Blue Tetra✅ Compatible
  Peaceful · 5 cm · Medium care · 22–28 °C (72–82 °F)
  • Compatible on the things that matter: shared water near 23–28 °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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Cochu's Blue Tetra in a shoal of 8+ or it gets stressed and nippy.
• Firehead Tetra✅ Compatible
  Peaceful · 5 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.
  • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Firehead Tetra in a shoal of 8+ or it gets stressed and nippy.
• Five-banded Barb✅ Compatible
  Peaceful · 5 cm · Easy care · 23–27 °C (73–81 °F)
  • Compatible on the things that matter: shared water near 23–27 °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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Five-banded Barb in a shoal of 6+ or it gets stressed and nippy.
• Forktail Blue-eye✅ Compatible
  Peaceful · 5 cm · Easy care · 22–28 °C (72–82 °F)
  • Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Forktail Blue-eye in a shoal of 6+ or it gets stressed and nippy.
• Half-striped Penguin Tetra✅ Compatible
  Peaceful · 5 cm · Medium care · 23–28 °C (73–82 °F)
  • Both are peaceful, and their water overlaps around 23–28 °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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Half-striped Penguin Tetra in a shoal of 6+ or it gets stressed and nippy.
• Honey Gourami✅ Compatible
  Peaceful · 5 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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
• Horseman Cory✅ Compatible
  Peaceful · 5 cm · Medium 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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Horseman Cory in a shoal of 6+ or it gets stressed and nippy.
• Japanese Trapdoor Snail✅ Compatible
  Peaceful · 5 cm · Easy care · 10–28 °C (50–82 °F)
  • Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
• Julii Corydoras✅ Compatible
  Peaceful · 5 cm · Easy care · 23–26 °C (73–79 °F)
  • Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Julii Corydoras in a shoal of 6+ or it gets stressed and nippy.
• Masked Corydoras✅ Compatible
  Peaceful · 5 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.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Masked Corydoras in a shoal of 6+ or it gets stressed and nippy.
• Mystery Snail✅ Compatible
  Peaceful · 5 cm · Easy care · 20–28 °C (68–82 °F)
  • Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
• Panda Corydoras✅ Compatible
  Peaceful · 5 cm · Medium care · 20–26 °C (68–79 °F)
  • Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Panda Corydoras in a shoal of 6+ or it gets stressed and nippy.
• Rummy-nose Tetra✅ Compatible
  Peaceful · 5 cm · Medium care · 23–29 °C (73–84 °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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Rummy-nose Tetra in a shoal of 6+ or it gets stressed and nippy.
• Skunk Corydoras✅ Compatible
  Peaceful · 5 cm · Easy care · 22–26 °C (72–79 °F)
  • Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Skunk Corydoras in a shoal of 6+ or it gets stressed and nippy.
• Stoliczka's Barb✅ Compatible
  Peaceful · 5 cm · Easy care · 20–26 °C (68–79 °F)
  • Both are peaceful, and their water overlaps around 23–26 °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 Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Stoliczka's Barb in a shoal of 6+ or it gets stressed and nippy.
• Xingu Black Neon Tetra✅ Compatible
  Peaceful · 5 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.
  • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Xingu Black Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
• Zebra Danio✅ Compatible
  Peaceful · 5 cm · Easy care · 18–25 °C (64–77 °F)
  • Both are peaceful, and their water overlaps around 23–25 °C — no size, zone or temperament conflicts.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Zebra Danio in a shoal of 6+ or it gets stressed and nippy.
• Amano Shrimp⚠️ With caution
  Peaceful · 5 cm · Easy care · 18–28 °C (64–82 °F)
  • Adult Amano Shrimp might survive with Harlequin Rasbora, but expect the young to be eaten — plant heavily.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
• Black Ruby Barb⚠️ With caution
  Semi-aggressive · 6 cm · Easy care · 22–26 °C (72–79 °F)
  • Black Ruby Barb is semi-aggressive and may chase or nip the smaller Harlequin Rasbora — plant heavily and break up sight lines.
  • Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • 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)
  • Expect Black Skirt Tetra to harass Harlequin Rasbora at times; give dense cover and watch them at feeding.
  • Keep Harlequin Rasbora 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.
• Blue Turbo Snail⚠️ With caution
  Peaceful · 5 cm · Medium care · 25–30 °C (77–86 °F)
  • pH preferences only just meet (Harlequin Rasbora 5.5–7 vs Blue Turbo Snail 7.5–8.5) — target the overlap and acclimate slowly.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
• Desert Goby⚠️ With caution
  Semi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
  • Desert Goby and Harlequin Rasbora are close in size, but the semi-aggressive one tends to dominate — add harlequin rasbora in a group to spread the pressure.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
• Dwarf Chain Loach⚠️ With caution
  Peaceful · 6 cm · Medium care · 24–29 °C (75–84 °F)
  • Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Dwarf Chain Loach in a shoal of 6+ or it gets stressed and nippy.
• Eastern Betta⚠️ With caution
  Semi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
  • Eastern Betta and Harlequin Rasbora are close in size, but the semi-aggressive one tends to dominate — add harlequin rasbora in a group to spread the pressure.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
• GloFish Tetra⚠️ With caution
  Semi-aggressive · 6 cm · Easy care · 21–28 °C (70–82 °F)
  • Expect GloFish Tetra to harass Harlequin Rasbora at times; give dense cover and watch them at feeding.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep GloFish Tetra in a shoal of 6+ or it gets stressed and nippy.
• Humpbacked Tetra⚠️ With caution
  Semi-aggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
  • Humpbacked Tetra is semi-aggressive and may chase or nip the smaller Harlequin Rasbora — plant heavily and break up sight lines.
  • Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Humpbacked Tetra in a shoal of 8+ or it gets stressed and nippy.
• Morse Code Corydoras⚠️ With caution
  Peaceful · 5 cm · Medium care · 23–26 °C (73–79 °F)
  • Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Morse Code Corydoras in a shoal of 6+ or it gets stressed and nippy.
• Odessa Barb⚠️ With caution
  Semi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
  • Odessa Barb is semi-aggressive and may chase or nip the smaller Harlequin Rasbora — plant heavily and break up sight lines.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Odessa Barb in a shoal of 6+ or it gets stressed and nippy.
• Panda Loach⚠️ With caution
  Peaceful · 6 cm · Hard care · 18–23 °C (64–73 °F)
  • Different pH ranges (5.5–7 vs 7.2–8.2); doable if you sit in the shared band, but not ideal long-term.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
• Silvertip Tetra⚠️ With caution
  Semi-aggressive · 5 cm · Easy care · 22–28 °C (72–82 °F)
  • Expect Silvertip Tetra to harass Harlequin Rasbora at times; give dense cover and watch them at feeding.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Keep Silvertip Tetra in a shoal of 6+ or it gets stressed and nippy.
• Spotfin Betta⚠️ With caution
  Semi-aggressive · 5 cm · Medium care · 23–28 °C (73–82 °F)
  • Spotfin Betta is semi-aggressive and may chase or nip the smaller Harlequin Rasbora — plant heavily and break up sight lines.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
• Striped Red-Eye Puffer⚠️ With caution
  Aggressive · 5 cm · Hard care · 24–28 °C (75–82 °F)
  • Striped Red-Eye Puffer and Harlequin Rasbora are close in size, but the aggressive one tends to dominate — add harlequin rasbora in a group to spread the pressure.
  • Keep Harlequin Rasbora in a shoal of 6+ or it gets stressed and nippy.
• Wine Red Betta⚠️ With caution
  Aggressive · 5 cm · Medium care · 24–28 °C (75–82 °F)
  • Wine Red Betta and Harlequin Rasbora are close in size, but the aggressive one tends to dominate — add harlequin rasbora in a group to spread the pressure.
  • Keep Harlequin Rasbora 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)
  • Harlequin Rasbora is bite-sized to a 250 cm predatory alligator gar — it will be eaten.
  • Alligator Gar is aggressive and may chase or nip the smaller Harlequin Rasbora — plant heavily and break up sight lines.
  • Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
  • Keep Harlequin Rasbora 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 5 cm Harlequin Rasbora whole.
  • Expect Clown Knifefish to harass Harlequin Rasbora at times; give dense cover and watch them at feeding.
  • Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
  • Keep Harlequin Rasbora 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)
  • Harlequin Rasbora is bite-sized to a 100 cm predatory fire eel — it will be eaten.
  • Fire Eel clearly outsizes Harlequin Rasbora and is semi-aggressive; risky unless the tank is big and well-planted.
  • Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
  • Keep Harlequin Rasbora 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 5 cm): Koi will treat Harlequin Rasbora as food.
  • Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
  • Keep Harlequin Rasbora 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)
  • Harlequin Rasbora is bite-sized to a 120 cm predatory redtail catfish — it will be eaten.
  • Redtail Catfish is aggressive and may chase or nip the smaller Harlequin Rasbora — plant heavily and break up sight lines.
  • Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
  • Keep Harlequin Rasbora 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)
  • Spotted Gar (90 cm) is big enough to swallow the 5 cm Harlequin Rasbora whole.
  • Expect Spotted Gar to harass Harlequin Rasbora 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 Harlequin Rasbora 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)
  • Size gap is too large (300 vs 5 cm): Wels Catfish will treat Harlequin Rasbora as food.
  • Wels Catfish clearly outsizes Harlequin Rasbora 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 Harlequin Rasbora 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)
  • Harlequin Rasbora is bite-sized to a 72 cm predatory wolf cichlid — it will be eaten.
  • Wolf Cichlid is aggressive and may chase or nip the smaller Harlequin Rasbora — plant heavily and break up sight lines.
  • Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
  • Keep Harlequin Rasbora 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.