Diamond Tetra Tank Mates

Diamond Tetra is peaceful, so its tank mates need choosing with care. Here are the 143 freshwater species that pair well with a diamond tetra — plus the 70 to avoid — with a live checker you can tune to your own tank.

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

The best tank mates for a diamond tetra

  • Ember Tetra ✅ Compatible
    Easy care · Peaceful · 2 cm · 24–28 °C (75–82 °F)
    Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
  • Neon Green Rasbora ✅ Compatible
    Easy care · Peaceful · 2 cm · 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.
  • Ramshorn Snail ✅ Compatible
    Easy care · Peaceful · 2 cm · 20–28 °C (68–82 °F)
    Compatible on the things that matter: shared water near 22–28 °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 22–28 °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 22–28 °C — no size, zone or temperament conflicts.
  • Nerite Snail ✅ Compatible
    Easy care · Peaceful · 2.5 cm · 22–28 °C (72–82 °F)
    Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
  • Assassin Snail ✅ Compatible
    Easy care · Peaceful · 3 cm · 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.
  • Endler's Livebearer ✅ 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.
  • Glowlight Danio ✅ Compatible
    Easy care · Peaceful · 3 cm · 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.
  • Gold Ring Danio ✅ Compatible
    Easy care · Peaceful · 3 cm · 18–26 °C (64–79 °F)
    Compatible on the things that matter: shared water near 22–26 °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, and their water overlaps around 22–27 °C — no size, zone or temperament conflicts.
  • Neon Tetra ✅ Compatible
    Easy care · Peaceful · 3 cm · 20–26 °C (68–79 °F)
    Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
  • Tail-spot Corydoras ✅ Compatible
    Easy care · Peaceful · 3 cm · 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.
  • Trinidad Guppy ✅ Compatible
    Easy care · Peaceful · 3 cm · 19–24 °C (66–75 °F)
    Compatible on the things that matter: shared water near 22–24 °C, workable temperaments, and no predator-and-prey size gap.
  • Pygmy Corydoras ✅ Compatible
    Easy care · Peaceful · 3.2 cm · 22–26 °C (72–79 °F)
    Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
  • Glowlight Rasbora ✅ Compatible
    Easy care · Peaceful · 3.5 cm · 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.
  • Blue Danio ✅ Compatible
    Easy care · Peaceful · 4 cm · 21–26 °C (70–79 °F)
    Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
  • Emperor Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 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.
  • Flame Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 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.
  • Glowlight Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 22–28 °C (72–82 °F)
    Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
  • Golden Dwarf Barb ✅ Compatible
    Easy care · Peaceful · 4 cm · 18–24 °C (64–75 °F)
    Compatible on the things that matter: shared water near 22–24 °C, workable temperaments, and no predator-and-prey size gap.
  • 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 22–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Rosy 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.
With caution

Diamond Tetra tank mates that can work with care

  • Afra Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 10 cm · 24–28 °C (75–82 °F)
    Different pH ranges (6–7.5 vs 7.8–8.6); doable if you sit in the shared band, but not ideal long-term.
  • African Butterfly Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 8 cm · 22–28 °C (72–82 °F)
    African Butterfly Cichlid is semi-aggressive and may chase or nip the smaller Diamond Tetra — plant heavily and break up sight lines.
  • Agassiz's Dwarf Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 9 cm · 24–30 °C (75–86 °F)
    Expect Agassiz's Dwarf Cichlid to harass Diamond Tetra at times; give dense cover and watch them at feeding.
  • Amano Shrimp ⚠️ With caution
    Easy care · Peaceful · 5 cm · 18–28 °C (64–82 °F)
    Diamond Tetra may eat Amano Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
  • 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)
    Angelfish clearly outsizes Diamond Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
  • Arrowhead Puffer ⚠️ With caution
    Hard care · Aggressive · 12 cm · 23–28 °C (73–82 °F)
    Arrowhead Puffer is aggressive and may chase or nip the smaller Diamond Tetra — plant heavily and break up sight lines.
  • Ash Lipped Apisto ⚠️ With caution
    Hard care · Semi-aggressive · 7 cm · 24–29 °C (75–84 °F)
    Expect Ash Lipped Apisto to harass Diamond Tetra at times; give dense cover and watch them at feeding.

+ 119 more “with caution” pairings — see the interactive checker above.

Avoid

Fish to avoid keeping with a diamond tetra

  • Wels Catfish ⛔ Avoid
    Hard care · Aggressive · 300 cm · 15–25 °C (59–77 °F)
    Size gap is too large (300 vs 6 cm): Wels Catfish will treat Diamond Tetra as food.
  • Alligator Gar ⛔ Avoid
    Hard care · Aggressive · 250 cm · 24–28 °C (75–82 °F)
    Diamond 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)
    Diamond 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 6 cm): Fire Eel will treat Diamond Tetra as food.
  • Clown Knifefish ⛔ Avoid
    Hard care · Aggressive · 90 cm · 24–28 °C (75–82 °F)
    Diamond Tetra is bite-sized to a 90 cm predatory clown knifefish — it will be eaten.
  • Koi ⛔ Avoid
    Medium care · Peaceful · 90 cm · 4–28 °C (39–82 °F)
    Koi (90 cm) is big enough to swallow the 6 cm Diamond Tetra whole.
  • Spotted Gar ⛔ Avoid
    Hard care · Aggressive · 90 cm · 18–26 °C (64–79 °F)
    Size gap is too large (90 vs 6 cm): Spotted Gar will treat Diamond Tetra as food.
  • Wolf Cichlid ⛔ Avoid
    Hard care · Aggressive · 72 cm · 24–30 °C (75–86 °F)
    Size gap is too large (72 vs 6 cm): Wolf Cichlid will treat Diamond Tetra as food.

+ 62 more to avoid — the checker above flags every one.

Interactive tool

Check any fish against a diamond tetra

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

Tank-mate checker

Will it live with a Diamond Tetra?

We compare each fish against your diamond tetra 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)
    • Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Diamond Tetra 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.
  • Agassiz's Corydoras✅ 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 Diamond 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.
  • Blackline Rasbora✅ 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.
    • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
    • Keep Diamond 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)
    • Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Diamond Tetra 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)
    • 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 Diamond Tetra 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.
  • Butterfly Hillstream Loach✅ Compatible
    Peaceful · 6 cm · Hard care · 18–24 °C (64–75 °F)
    • Compatible on the things that matter: shared water near 22–24 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Diamond Tetra 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 Diamond 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.
  • Duplicareus Corydoras✅ Compatible
    Peaceful · 5.5 cm · Medium 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.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
    • 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)
    • Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
    • Keep Diamond 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.
  • False Julii Corydoras✅ Compatible
    Peaceful · 6 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 Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
    • 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)
    • Both are peaceful, and their water overlaps around 27–28 °C — no size, zone or temperament conflicts.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Glass Bloodfin Tetra✅ 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.
    • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Glass Bloodfin Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Guppy✅ 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.
    • Keep Diamond Tetra 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)
    • Compatible on the things that matter: shared water near 22–24 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Narcissus II Cory✅ Compatible
    Peaceful · 5.5 cm · Medium care · 22–26 °C (72–79 °F)
    • Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Narcissus II Cory in a shoal of 6+ or it gets stressed and nippy.
  • Neon Dwarf Rainbowfish✅ Compatible
    Peaceful · 6 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 Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Neon Dwarf Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
  • Panda Loach✅ Compatible
    Peaceful · 6 cm · Hard care · 18–23 °C (64–73 °F)
    • Compatible on the things that matter: shared water near 22–23 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Pearl Danio✅ Compatible
    Peaceful · 6 cm · Easy care · 20–25 °C (68–77 °F)
    • Both are peaceful, and their water overlaps around 22–25 °C — no size, zone or temperament conflicts.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Pearl Danio in a shoal of 6+ or it gets stressed and nippy.
  • Platy✅ Compatible
    Peaceful · 6 cm · Easy care · 21–28 °C (70–82 °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 Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Rust Corydoras✅ Compatible
    Peaceful · 5.5 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.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Rust Corydoras in a shoal of 6+ or it gets stressed and nippy.
  • Samurai Gourami✅ Compatible
    Peaceful · 6 cm · Hard 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.
    • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
    • Keep Diamond Tetra 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)
    • Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
    • 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)
    • Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Diamond 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.
  • 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 Diamond 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.
  • Ash Lipped Apisto⚠️ With caution
    Semi-aggressive · 7 cm · Hard care · 24–29 °C (75–84 °F)
    • Expect Ash Lipped Apisto to harass Diamond Tetra at times; give dense cover and watch them at feeding.
    • Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
    • Keep Diamond 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)
    • Banded Dwarf Cichlid and Diamond Tetra are close in size, but the semi-aggressive one tends to dominate — add diamond tetra in a group to spread the pressure.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Betta⚠️ With caution
    Semi-aggressive · 6.5 cm · Easy care · 24–28 °C (75–82 °F)
    • Betta is semi-aggressive and may chase or nip the smaller Diamond Tetra — plant heavily and break up sight lines.
    • Keep Diamond Tetra 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)
    • Expect Black Ruby Barb to harass Diamond Tetra at times; give dense cover and watch them at feeding.
    • Your 75 L tank is below the ~100 L this pairing really wants — crowding raises aggression.
    • Keep Diamond Tetra 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)
    • Black Skirt Tetra and Diamond Tetra are close in size, but the semi-aggressive one tends to dominate — add diamond tetra in a group to spread the pressure.
    • Keep Diamond 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.
  • Bleeding Heart Tetra⚠️ With caution
    Semi-aggressive · 7 cm · Medium care · 23–28 °C (73–82 °F)
    • Bleeding Heart Tetra and Diamond Tetra are close in size, but the semi-aggressive one tends to dominate — add diamond 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 Diamond 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 Diamond 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.
  • Colombian Tetra⚠️ With caution
    Semi-aggressive · 6.5 cm · Easy care · 24–28 °C (75–82 °F)
    • Colombian Tetra is semi-aggressive and may chase or nip the smaller Diamond Tetra — plant heavily and break up sight lines.
    • Your 75 L tank is below the ~114 L this pairing really wants — crowding raises aggression.
    • Keep Diamond 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.
  • Desert Goby⚠️ With caution
    Semi-aggressive · 6 cm · Easy care · 18–28 °C (64–82 °F)
    • Desert Goby is semi-aggressive and may chase or nip the smaller Diamond Tetra — plant heavily and break up sight lines.
    • Keep Diamond Tetra 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 Diamond Tetra 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 is semi-aggressive and may chase or nip the smaller Diamond Tetra — plant heavily and break up sight lines.
    • Keep Diamond Tetra 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 and Diamond Tetra are close in size, but the semi-aggressive one tends to dominate — add diamond tetra in a group to spread the pressure.
    • Keep Diamond Tetra 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.
  • Odessa Barb⚠️ With caution
    Semi-aggressive · 6 cm · Easy care · 20–26 °C (68–79 °F)
    • Expect Odessa Barb to harass Diamond Tetra at times; give dense cover and watch them at feeding.
    • Keep Diamond Tetra 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.
  • Peaceful Betta⚠️ With caution
    Semi-aggressive · 6 cm · Medium care · 24–28 °C (75–82 °F)
    • Expect Peaceful Betta to harass Diamond Tetra at times; give dense cover and watch them at feeding.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Smaragd Betta⚠️ With caution
    Aggressive · 6 cm · Medium care · 23–28 °C (73–82 °F)
    • Smaragd Betta and Diamond Tetra are close in size, but the aggressive one tends to dominate — add diamond tetra in a group to spread the pressure.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Three-striped Dwarf Cichlid⚠️ With caution
    Semi-aggressive · 6 cm · Medium care · 23–29 °C (73–84 °F)
    • Three-striped Dwarf Cichlid and Diamond Tetra are close in size, but the semi-aggressive one tends to dominate — add diamond tetra in a group to spread the pressure.
    • Keep Diamond 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)
    • Diamond 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 Diamond 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 Diamond 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)
    • Diamond Tetra is bite-sized to a 90 cm predatory clown knifefish — it will be eaten.
    • Clown Knifefish is aggressive and may chase or nip the smaller Diamond 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 Diamond 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)
    • Size gap is too large (100 vs 6 cm): Fire Eel will treat Diamond Tetra as food.
    • Expect Fire Eel to harass Diamond 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 Diamond 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)
    • Koi (90 cm) is big enough to swallow the 6 cm Diamond Tetra whole.
    • Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
    • Keep Diamond 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)
    • Diamond Tetra 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 Diamond Tetra — plant heavily and break up sight lines.
    • Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
    • Keep Diamond 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)
    • Size gap is too large (90 vs 6 cm): Spotted Gar will treat Diamond Tetra as food.
    • Expect Spotted Gar to harass Diamond 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 Diamond 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)
    • Size gap is too large (300 vs 6 cm): Wels Catfish will treat Diamond Tetra as food.
    • Expect Wels Catfish to harass Diamond 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 Diamond 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)
    • Size gap is too large (72 vs 6 cm): Wolf Cichlid will treat Diamond Tetra as food.
    • Expect Wolf Cichlid to harass Diamond 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 Diamond 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.

Setting up a diamond 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 diamond tetra

As a peaceful species, diamond 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.

Diamond Tetra grows to about 6 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 22–28 °C (72–82 °F), pH 6–7.5 and 3–12 dGH. Fish needing very different conditions — coldwater species, or hard-water lovers against a soft-water fish — rarely thrive side by side.

Diamond Tetra is a shoaling fish — stock a group of 6+ 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 diamond tetra live with other fish?

Yes — with the right companions. Our checker finds 143 compatible freshwater species for diamond 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 diamond 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 diamond 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 diamond tetra tank mates need?

Start from Diamond 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 Diamond Tetra care guide