Ruby Tetra Tank Mates

Ruby Tetra is peaceful, so its tank mates need choosing with care. Here are the 132 freshwater species that pair well with a ruby tetra — plus the 105 to avoid — with a live checker you can tune to your own tank.

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

The best tank mates for a ruby tetra

  • Ember Tetra ✅ Compatible
    Easy care · Peaceful · 2 cm · 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.
  • Neon Green Rasbora ✅ Compatible
    Easy care · Peaceful · 2 cm · 22–26 °C (72–79 °F)
    Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
  • Ramshorn Snail ✅ Compatible
    Easy care · Peaceful · 2 cm · 20–28 °C (68–82 °F)
    Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Red Lip Nerite Snail ✅ Compatible
    Easy care · Peaceful · 2 cm · 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.
  • Dawn Tetra ✅ Compatible
    Easy care · Peaceful · 2.5 cm · 22–28 °C (72–82 °F)
    Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
  • Nerite Snail ✅ Compatible
    Easy care · Peaceful · 2.5 cm · 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.
  • Assassin Snail ✅ Compatible
    Easy care · Peaceful · 3 cm · 22–26 °C (72–79 °F)
    Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
  • Cherry Shrimp ✅ Compatible
    Easy care · Peaceful · 3 cm · 18–28 °C (64–82 °F)
    Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
  • Glowlight Danio ✅ Compatible
    Easy care · Peaceful · 3 cm · 22–26 °C (72–79 °F)
    Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
  • Gold Ring Danio ✅ Compatible
    Easy care · Peaceful · 3 cm · 18–26 °C (64–79 °F)
    Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
  • Malaysian Trumpet Snail ✅ Compatible
    Easy care · Peaceful · 3 cm · 21–27 °C (70–81 °F)
    Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Neon Tetra ✅ Compatible
    Easy care · Peaceful · 3 cm · 20–26 °C (68–79 °F)
    Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
  • Tail-spot Corydoras ✅ Compatible
    Easy care · Peaceful · 3 cm · 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.
  • Trinidad Guppy ✅ Compatible
    Easy care · Peaceful · 3 cm · 19–24 °C (66–75 °F)
    Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Pygmy Corydoras ✅ Compatible
    Easy care · Peaceful · 3.2 cm · 22–26 °C (72–79 °F)
    Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
  • Glowlight Rasbora ✅ Compatible
    Easy care · Peaceful · 3.5 cm · 23–28 °C (73–82 °F)
    Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Blue Danio ✅ Compatible
    Easy care · Peaceful · 4 cm · 21–26 °C (70–79 °F)
    Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
  • Emperor Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 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.
  • Flame Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 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.
  • Ghost Shrimp ✅ Compatible
    Easy care · Peaceful · 4 cm · 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.
  • Glowlight Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 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.
  • Golden Dwarf Barb ✅ Compatible
    Easy care · Peaceful · 4 cm · 18–24 °C (64–75 °F)
    Both are peaceful, and their water overlaps around 23–24 °C — no size, zone or temperament conflicts.
  • Phoenix Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 23–28 °C (73–82 °F)
    Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Red Phantom Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 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.
With caution

Ruby Tetra tank mates that can work with care

  • African Butterfly Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 8 cm · 22–28 °C (72–82 °F)
    Expect African Butterfly Cichlid to harass Ruby Tetra at times; give dense cover and watch them at feeding.
  • 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)
    Expect Angelfish to harass Ruby Tetra at times; give dense cover and watch them at feeding.
  • Banded Gourami ⚠️ With caution
    Easy care · Semi-aggressive · 12 cm · 22–28 °C (72–82 °F)
    Banded Gourami is semi-aggressive and may chase or nip the smaller Ruby Tetra — plant heavily and break up sight lines.
  • Bandit Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 9 cm · 22–26 °C (72–79 °F)
    Expect Bandit Cichlid to harass Ruby Tetra at times; give dense cover and watch them at feeding.
  • Bearded Corydoras ⚠️ With caution
    Medium care · Peaceful · 10 cm · 18–24 °C (64–75 °F)
    Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
  • Black Darter Tetra ⚠️ With caution
    Hard care · Semi-aggressive · 4 cm · 21–28 °C (70–82 °F)
    Black Darter Tetra clearly outsizes Ruby Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
  • Black Ruby Barb ⚠️ With caution
    Easy care · Semi-aggressive · 6 cm · 22–26 °C (72–79 °F)
    Black Ruby Barb clearly outsizes Ruby Tetra and is semi-aggressive; risky unless the tank is big and well-planted.

+ 95 more “with caution” pairings — see the interactive checker above.

Avoid

Fish to avoid keeping with a ruby tetra

  • Wels Catfish ⛔ Avoid
    Hard care · Aggressive · 300 cm · 15–25 °C (59–77 °F)
    Ruby Tetra is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
  • Alligator Gar ⛔ Avoid
    Hard care · Aggressive · 250 cm · 24–28 °C (75–82 °F)
    Ruby Tetra is bite-sized to a 250 cm predatory alligator gar — it will be eaten.
  • Redtail Catfish ⛔ Avoid
    Hard care · Aggressive · 120 cm · 24–27 °C (75–81 °F)
    Ruby Tetra is bite-sized to a 120 cm predatory redtail catfish — it will be eaten.
  • Fire Eel ⛔ Avoid
    Medium care · Semi-aggressive · 100 cm · 24–28 °C (75–82 °F)
    Size gap is too large (100 vs 2 cm): Fire Eel will treat Ruby Tetra as food.
  • Clown Knifefish ⛔ Avoid
    Hard care · Aggressive · 90 cm · 24–28 °C (75–82 °F)
    Clown Knifefish (90 cm) is big enough to swallow the 2 cm Ruby Tetra whole.
  • Koi ⛔ Avoid
    Medium care · Peaceful · 90 cm · 4–28 °C (39–82 °F)
    Koi (90 cm) is big enough to swallow the 2 cm Ruby Tetra whole.
  • Spotted Gar ⛔ Avoid
    Hard care · Aggressive · 90 cm · 18–26 °C (64–79 °F)
    Ruby Tetra is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
  • Wolf Cichlid ⛔ Avoid
    Hard care · Aggressive · 72 cm · 24–30 °C (75–86 °F)
    Wolf Cichlid (72 cm) is big enough to swallow the 2 cm Ruby Tetra whole.

+ 97 more to avoid — the checker above flags every one.

Interactive tool

Check any fish against a ruby tetra

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

Tank-mate checker

Will it live with a Ruby Tetra?

We compare each fish against your ruby tetra on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.

  • Assassin Snail✅ Compatible
    Peaceful · 3 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Celestial Pearl Danio✅ Compatible
    Peaceful · 2 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.
    • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Celestial Pearl Danio in a shoal of 6+ or it gets stressed and nippy.
  • Cherry Shrimp✅ Compatible
    Peaceful · 3 cm · Easy care · 18–28 °C (64–82 °F)
    • Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Cherry Shrimp in a shoal of 10+ or it gets stressed and nippy.
  • Chili Rasbora✅ Compatible
    Peaceful · 2 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Chili Rasbora in a shoal of 8+ or it gets stressed and nippy.
  • Crystal Red Shrimp✅ Compatible
    Peaceful · 2.5 cm · Hard care · 20–24 °C (68–75 °F)
    • Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Crystal Red Shrimp in a shoal of 10+ or it gets stressed and nippy.
  • Dawn Tetra✅ Compatible
    Peaceful · 2.5 cm · Easy care · 22–28 °C (72–82 °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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Dawn Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Dwarf Spotted Rasbora✅ Compatible
    Peaceful · 2.5 cm · Medium 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.
    • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Dwarf Spotted Rasbora in a shoal of 8+ or it gets stressed and nippy.
  • Ember Tetra✅ Compatible
    Peaceful · 2 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Ember Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Emerald Dwarf Danio✅ Compatible
    Peaceful · 2 cm · Medium care · 20–24 °C (68–75 °F)
    • Both are peaceful, and their water overlaps around 23–24 °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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Emerald Dwarf Danio in a shoal of 8+ or it gets stressed and nippy.
  • Exclamation Point Rasbora✅ Compatible
    Peaceful · 2 cm · Medium care · 22–28 °C (72–82 °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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Exclamation Point Rasbora in a shoal of 8+ or it gets stressed and nippy.
  • Glowlight Danio✅ Compatible
    Peaceful · 3 cm · Easy care · 22–26 °C (72–79 °F)
    • Compatible on the things that matter: shared water near 23–26 °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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
  • Gold Ring Danio✅ Compatible
    Peaceful · 3 cm · Easy care · 18–26 °C (64–79 °F)
    • Compatible on the things that matter: shared water near 23–26 °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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Gold Ring Danio in a shoal of 8+ or it gets stressed and nippy.
  • Green Neon Tetra✅ Compatible
    Peaceful · 2.5 cm · Hard care · 24–28 °C (75–82 °F)
    • Both are peaceful, and their water overlaps around 24–28 °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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Green Neon Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Hummingbird Tetra✅ Compatible
    Peaceful · 1.8 cm · Hard care · 22–27 °C (72–81 °F)
    • Both are peaceful, and their water overlaps around 23–27 °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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Hummingbird Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Lambchop Rasbora✅ Compatible
    Peaceful · 3 cm · Medium 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.
    • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Lambchop Rasbora in a shoal of 6+ or it gets stressed and nippy.
  • Malaysian Trumpet Snail✅ Compatible
    Peaceful · 3 cm · Easy care · 21–27 °C (70–81 °F)
    • Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Neon Blue Rasbora✅ Compatible
    Peaceful · 2.5 cm · Medium care · 23–26 °C (73–79 °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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Neon Blue Rasbora in a shoal of 10+ or it gets stressed and nippy.
  • Neon Green Rasbora✅ Compatible
    Peaceful · 2 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.
    • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Neon Green Rasbora in a shoal of 10+ or it gets stressed and nippy.
  • Neon Tetra✅ Compatible
    Peaceful · 3 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Neon Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Nerite Snail✅ Compatible
    Peaceful · 2.5 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Ramshorn Snail✅ Compatible
    Peaceful · 2 cm · Easy care · 20–28 °C (68–82 °F)
    • Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Red Lip Nerite Snail✅ Compatible
    Peaceful · 2 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Strawberry Rasbora✅ Compatible
    Peaceful · 2 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Strawberry Rasbora in a shoal of 8+ or it gets stressed and nippy.
  • Tucano Tetra✅ Compatible
    Peaceful · 1.7 cm · Hard care · 23–28 °C (73–82 °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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Tucano Tetra in a shoal of 10+ or it gets stressed and nippy.
  • Black Darter Tetra⚠️ With caution
    Semi-aggressive · 4 cm · Hard care · 21–28 °C (70–82 °F)
    • Black Darter Tetra clearly outsizes Ruby Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
    • Ruby Tetra is small enough to tempt Black Darter Tetra; only risk it in a densely planted setup with hiding spots.
    • Keep Ruby Tetra in a shoal of 8+ 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 clearly outsizes Ruby Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
    • Black Ruby Barb may hunt Ruby Tetra, fry or shrimplets — safest in a heavily planted tank.
    • Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
    • Keep Ruby Tetra in a shoal of 8+ 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)
    • Black Skirt Tetra is semi-aggressive and may chase or nip the smaller Ruby Tetra — plant heavily and break up sight lines.
    • Ruby Tetra is small enough to tempt Black Skirt Tetra; only risk it in a densely planted setup with hiding spots.
    • Keep Ruby Tetra in a shoal of 8+ 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)
    • Different pH ranges (5.5–7 vs 7.5–8.5); doable if you sit in the shared band, but not ideal long-term.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Desert Goby⚠️ With caution
    Semi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
    • Desert Goby clearly outsizes Ruby Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
    • Watch for Desert Goby picking off any ruby tetra small enough to fit in its mouth.
    • Keep Ruby Tetra in a shoal of 8+ 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Dwarf Chain Loach in a shoal of 6+ or it gets stressed and nippy.
  • Endler's Livebearer⚠️ With caution
    Peaceful · 3 cm · Easy care · 22–28 °C (72–82 °F)
    • Water hardness preferences differ (Ruby Tetra 1–8 vs Endler's Livebearer 10–25 dGH).
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Endler's Livebearer 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)
    • GloFish Tetra clearly outsizes Ruby Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
    • GloFish Tetra may hunt Ruby Tetra, fry or shrimplets — safest in a heavily planted tank.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep GloFish Tetra in a shoal of 6+ 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 Ruby Tetra in a shoal of 8+ 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 Ruby Tetra — plant heavily and break up sight lines.
    • Odessa Barb may hunt Ruby Tetra, fry or shrimplets — safest in a heavily planted tank.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Odessa Barb in a shoal of 6+ or it gets stressed and nippy.
  • Pea Puffer⚠️ With caution
    Semi-aggressive · 2.5 cm · Medium care · 24–28 °C (75–82 °F)
    • Pea Puffer is semi-aggressive and may chase or nip the smaller Ruby Tetra — plant heavily and break up sight lines.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Rainbow Emperor Tetra⚠️ With caution
    Semi-aggressive · 3.6 cm · Medium care · 22–28 °C (72–82 °F)
    • Rainbow Emperor Tetra clearly outsizes Ruby Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
    • Rainbow Emperor Tetra may hunt Ruby Tetra, fry or shrimplets — safest in a heavily planted tank.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Scarlet Badis⚠️ With caution
    Semi-aggressive · 2 cm · Medium care · 22–27 °C (72–81 °F)
    • Expect Scarlet Badis to harass Ruby Tetra at times; give dense cover and watch them at feeding.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Serpae Tetra⚠️ With caution
    Semi-aggressive · 4 cm · Easy care · 23–28 °C (73–82 °F)
    • Serpae Tetra is semi-aggressive and may chase or nip the smaller Ruby Tetra — plant heavily and break up sight lines.
    • Ruby Tetra is small enough to tempt Serpae Tetra; only risk it in a densely planted setup with hiding spots.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Serpae Tetra 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 Ruby Tetra at times; give dense cover and watch them at feeding.
    • Silvertip Tetra may hunt Ruby Tetra, fry or shrimplets — safest in a heavily planted tank.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Silvertip Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Tiger Badis⚠️ With caution
    Semi-aggressive · 4 cm · Medium care · 22–24 °C (72–75 °F)
    • Expect Tiger Badis to harass Ruby Tetra at times; give dense cover and watch them at feeding.
    • Ruby Tetra is small enough to tempt Tiger Badis; only risk it in a densely planted setup with hiding spots.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Alligator Gar⛔ Not recommended
    Aggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
    • Ruby Tetra 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 Ruby Tetra — plant heavily and break up sight lines.
    • Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
    • Keep Ruby Tetra in a shoal of 8+ 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 2 cm Ruby Tetra whole.
    • Clown Knifefish is aggressive and may chase or nip the smaller Ruby 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Fire Eel⛔ Not recommended
    Semi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
    • Size gap is too large (100 vs 2 cm): Fire Eel will treat Ruby Tetra as food.
    • Fire Eel clearly outsizes Ruby Tetra 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Koi⛔ Not recommended
    Peaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
    • Koi (90 cm) is big enough to swallow the 2 cm Ruby Tetra whole.
    • Water hardness preferences differ (Ruby Tetra 1–8 vs Koi 9–18 dGH).
    • Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Redtail Catfish⛔ Not recommended
    Aggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
    • Ruby Tetra is bite-sized to a 120 cm predatory redtail catfish — it will be eaten.
    • Expect Redtail Catfish to harass Ruby 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 Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Spotted Gar⛔ Not recommended
    Aggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
    • Ruby Tetra is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
    • Spotted Gar clearly outsizes Ruby Tetra and is aggressive; risky unless the tank is big and well-planted.
    • Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
    • Keep Ruby Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Wels Catfish⛔ Not recommended
    Aggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
    • Ruby Tetra is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
    • Expect Wels Catfish to harass Ruby Tetra at times; give dense cover and watch them at feeding.
    • Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
    • Keep Ruby Tetra in a shoal of 8+ 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 2 cm Ruby Tetra whole.
    • Wolf Cichlid is aggressive and may chase or nip the smaller Ruby Tetra — plant heavily and break up sight lines.
    • Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
    • Keep Ruby Tetra in a shoal of 8+ 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.

Setting up a ruby tetra 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 ruby tetra

As a peaceful species, ruby tetra is easily bullied — favour other calm, non-nippy fish and steer clear of boisterous or aggressive tank mates. It mostly occupies the middle of the tank, so it pairs naturally with species that use the other levels.

Ruby Tetra grows to about 2 cm, so avoid tank mates small enough to be seen as food — as a rule of thumb, skip anything under roughly 2 cm. Match its water, too: aim for 23–28 °C (73–82 °F), pH 5.5–7 and 1–8 dGH. Fish needing very different conditions — coldwater species, or hard-water lovers against a soft-water fish — rarely thrive side by side.

Ruby Tetra is a shoaling fish — stock a group of 8+ of its own kind first, then build compatible tank mates around them. 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 ruby tetra live with other fish?

Yes — with the right companions. Our checker finds 132 compatible freshwater species for ruby tetra. 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 ruby tetra?

Easy, peaceful, similarly-sized species top the list — for example Ember Tetra, Neon Green Rasbora, Ramshorn Snail. Use the checker above to match against your own tank size.

What fish should you avoid keeping with a ruby tetra?

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 ruby tetra tank mates need?

Start from Ruby Tetra'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.

← Back to the full Ruby Tetra care guide