Bright Diamond Tetra Tank Mates

Bright Diamond Tetra is peaceful, so its tank mates need choosing with care. Here are the 149 freshwater species that pair well with a bright diamond tetra — plus the 67 to avoid — with a live checker you can tune to your own tank.

By The Aquarium DB Team • Updated June 8, 2026 • Full Bright Diamond Tetra care guide →
Best matches

The best tank mates for a bright diamond tetra

  • Ember Tetra ✅ Compatible
    Easy care · Peaceful · 2 cm · 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.
  • Neon Green Rasbora ✅ Compatible
    Easy care · Peaceful · 2 cm · 22–26 °C (72–79 °F)
    Both are peaceful, and their water overlaps around 24–26 °C — no size, zone or temperament conflicts.
  • Dawn Tetra ✅ Compatible
    Easy care · Peaceful · 2.5 cm · 22–28 °C (72–82 °F)
    Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
  • Assassin Snail ✅ Compatible
    Easy care · Peaceful · 3 cm · 22–26 °C (72–79 °F)
    Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
  • 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)
    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 24–26 °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)
    Compatible on the things that matter: shared water near 24–26 °C, workable temperaments, and no predator-and-prey size gap.
  • 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; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • 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 24–28 °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 24–28 °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 24–24 °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, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
  • Red Phantom 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.
  • 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.
  • Serpae Tetra ✅ Compatible
    Easy care · Semi-aggressive · 4 cm · 23–28 °C (73–82 °F)
    Peaceful + Semi-aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Yellow Phantom Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 23–27 °C (73–81 °F)
    Compatible on the things that matter: shared water near 24–27 °C, workable temperaments, and no predator-and-prey size gap.
  • Black Phantom Tetra ✅ Compatible
    Easy care · Peaceful · 4.5 cm · 22–28 °C (72–82 °F)
    Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
  • Gold Tetra ✅ Compatible
    Easy care · Peaceful · 4.5 cm · 23–28 °C (73–82 °F)
    Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
  • Lemon Tetra ✅ Compatible
    Easy care · Peaceful · 4.5 cm · 23–28 °C (73–82 °F)
    Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
With caution

Bright 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)
    pH preferences only just meet (Bright Diamond Tetra 5.5–6.8 vs Afra Cichlid 7.8–8.6) — target the overlap and acclimate slowly.
  • African Butterfly Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 8 cm · 22–28 °C (72–82 °F)
    African Butterfly Cichlid and Bright Diamond Tetra are close in size, but the semi-aggressive one tends to dominate — add bright diamond tetra in a group to spread the pressure.
  • 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 Bright 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)
    Adult Amano Shrimp might survive with Bright Diamond Tetra, but expect the young to be eaten — plant heavily.
  • Amazon Puffer ⚠️ With caution
    Medium care · Peaceful · 8 cm · 23–28 °C (73–82 °F)
    Your 80 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 is semi-aggressive and may chase or nip the smaller Bright Diamond Tetra — plant heavily and break up sight lines.
  • 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 Bright 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)
    Ash Lipped Apisto and Bright Diamond Tetra are close in size, but the semi-aggressive one tends to dominate — add bright diamond tetra in a group to spread the pressure.

+ 116 more “with caution” pairings — see the interactive checker above.

Avoid

Fish to avoid keeping with a bright diamond tetra

  • Wels Catfish ⛔ Avoid
    Hard care · Aggressive · 300 cm · 15–25 °C (59–77 °F)
    Wels Catfish (300 cm) is big enough to swallow the 7 cm Bright Diamond Tetra whole.
  • Alligator Gar ⛔ Avoid
    Hard care · Aggressive · 250 cm · 24–28 °C (75–82 °F)
    Bright 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)
    Redtail Catfish (120 cm) is big enough to swallow the 7 cm Bright Diamond Tetra whole.
  • Fire Eel ⛔ Avoid
    Medium care · Semi-aggressive · 100 cm · 24–28 °C (75–82 °F)
    Bright Diamond Tetra is bite-sized to a 100 cm predatory fire eel — it will be eaten.
  • Clown Knifefish ⛔ Avoid
    Hard care · Aggressive · 90 cm · 24–28 °C (75–82 °F)
    Size gap is too large (90 vs 7 cm): Clown Knifefish will treat Bright Diamond Tetra as food.
  • Koi ⛔ Avoid
    Medium care · Peaceful · 90 cm · 4–28 °C (39–82 °F)
    Size gap is too large (90 vs 7 cm): Koi will treat Bright Diamond Tetra as food.
  • Spotted Gar ⛔ Avoid
    Hard care · Aggressive · 90 cm · 18–26 °C (64–79 °F)
    Spotted Gar (90 cm) is big enough to swallow the 7 cm Bright Diamond Tetra whole.
  • Wolf Cichlid ⛔ Avoid
    Hard care · Aggressive · 72 cm · 24–30 °C (75–86 °F)
    Size gap is too large (72 vs 7 cm): Wolf Cichlid will treat Bright Diamond Tetra as food.

+ 59 more to avoid — the checker above flags every one.

Interactive tool

Check any fish against a bright diamond tetra

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

Tank-mate checker

Will it live with a Bright Diamond Tetra?

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

  • Agassiz's Corydoras✅ Compatible
    Peaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
    • Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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)
    • Compatible on the things that matter: shared water near 24–27 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Black Kuhli Loach✅ Compatible
    Peaceful · 8 cm · Easy care · 23–28 °C (73–82 °F)
    • Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 24–26 °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 Bright Diamond 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.
  • 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 Bright Diamond Tetra in a shoal of 8+ 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, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 Bright Diamond Tetra in a shoal of 8+ 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 Bright Diamond Tetra in a shoal of 8+ 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 24–26 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Corydoras Catfish in a shoal of 6+ or it gets stressed and nippy.
  • Costa's Tetra✅ Compatible
    Peaceful · 7 cm · Easy care · 22–28 °C (72–82 °F)
    • 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 Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Costa's Tetra 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)
    • 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 Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Diamond Tetra✅ Compatible
    Peaceful · 6 cm · Easy care · 22–28 °C (72–82 °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 Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Diamond Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Glass Catfish✅ Compatible
    Peaceful · 8 cm · Medium 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 Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Glass Catfish 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)
    • Compatible on the things that matter: shared water near 24–26 °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 Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Gold Barb in a shoal of 6+ or it gets stressed and nippy.
  • Melon Barb✅ Compatible
    Peaceful · 7 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 Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Melon Barb in a shoal of 8+ or it gets stressed and nippy.
  • Peacock Gudgeon✅ Compatible
    Peaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
    • Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
    • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
    • Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Peppered Corydoras✅ Compatible
    Peaceful · 7 cm · Easy care · 18–26 °C (64–79 °F)
    • Both are peaceful, and their water overlaps around 24–26 °C — no size, zone or temperament conflicts.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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)
    • Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Rounded Filament Barb✅ Compatible
    Peaceful · 7 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.
    • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
    • Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Rounded Filament Barb 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 24–28 °C — no size, zone or temperament conflicts.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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, and their water overlaps around 24–26 °C — no size, zone or temperament conflicts.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 24–27 °C — no size, zone or temperament conflicts.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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)
    • Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 and Bright Diamond Tetra are close in size, but the semi-aggressive one tends to dominate — add bright diamond tetra in a group to spread the pressure.
    • Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Amazon Puffer⚠️ With caution
    Peaceful · 8 cm · Medium care · 23–28 °C (73–82 °F)
    • Your 80 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 Bright Diamond Tetra are close in size, but the semi-aggressive one tends to dominate — add bright diamond tetra in a group to spread the pressure.
    • Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Badis⚠️ With caution
    Semi-aggressive · 8 cm · Medium care · 22–28 °C (72–82 °F)
    • Expect Badis to harass Bright Diamond Tetra at times; give dense cover and watch them at feeding.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 is semi-aggressive and may chase or nip the smaller Bright Diamond Tetra — plant heavily and break up sight lines.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 Bright Diamond Tetra — plant heavily and break up sight lines.
    • Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Bleeding Heart Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Buenos Aires Tetra⚠️ With caution
    Semi-aggressive · 7 cm · Easy care · 18–26 °C (64–79 °F)
    • Expect Buenos Aires Tetra to harass Bright Diamond Tetra at times; give dense cover and watch them at feeding.
    • Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Celebes Rainbowfish⚠️ With caution
    Peaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
    • Different pH ranges (5.5–6.8 vs 7–8.5); doable if you sit in the shared band, but not ideal long-term.
    • Water hardness preferences differ (Bright Diamond Tetra 1–8 vs Celebes Rainbowfish 10–20 dGH).
    • Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Celebes Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
  • Cockatoo Dwarf Cichlid⚠️ With caution
    Semi-aggressive · 8 cm · Medium care · 24–28 °C (75–82 °F)
    • Cockatoo Dwarf Cichlid is semi-aggressive and may chase or nip the smaller Bright Diamond Tetra — plant heavily and break up sight lines.
    • 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)
    • Your 80 L tank is below the ~114 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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)
    • Expect Hongsloi Dwarf Cichlid to harass Bright Diamond Tetra at times; give dense cover and watch them at feeding.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 Bright Diamond Tetra at times; give dense cover and watch them at feeding.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 Bright Diamond Tetra at times; give dense cover and watch them at feeding.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 Bright Diamond Tetra are close in size, but the semi-aggressive one tends to dominate — add bright diamond tetra in a group to spread the pressure.
    • Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Tiger Barb⚠️ With caution
    Semi-aggressive · 7 cm · Easy care · 22–28 °C (72–82 °F)
    • Expect Tiger Barb to harass Bright Diamond Tetra at times; give dense cover and watch them at feeding.
    • Your 80 L tank is below the ~95 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond Tetra in a shoal of 8+ 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 Bright Diamond Tetra — plant heavily and break up sight lines.
    • Keep Bright Diamond 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)
    • Bright Diamond Tetra is bite-sized to a 250 cm predatory alligator gar — it will be eaten.
    • Alligator Gar clearly outsizes Bright Diamond Tetra and is aggressive; risky unless the tank is big and well-planted.
    • Your 80 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond 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)
    • Size gap is too large (90 vs 7 cm): Clown Knifefish will treat Bright Diamond Tetra as food.
    • Clown Knifefish clearly outsizes Bright Diamond Tetra and is aggressive; risky unless the tank is big and well-planted.
    • Your 80 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond 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)
    • Bright Diamond Tetra is bite-sized to a 100 cm predatory fire eel — it will be eaten.
    • Fire Eel clearly outsizes Bright Diamond Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
    • Your 80 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond 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)
    • Size gap is too large (90 vs 7 cm): Koi will treat Bright Diamond Tetra as food.
    • One likes softer water and the other harder (1–8 vs 9–18 dGH) — a compromise, not a perfect match.
    • Your 80 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond 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)
    • Redtail Catfish (120 cm) is big enough to swallow the 7 cm Bright Diamond Tetra whole.
    • Redtail Catfish is aggressive and may chase or nip the smaller Bright Diamond Tetra — plant heavily and break up sight lines.
    • Your 80 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond 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)
    • Spotted Gar (90 cm) is big enough to swallow the 7 cm Bright Diamond Tetra whole.
    • Expect Spotted Gar to harass Bright Diamond Tetra at times; give dense cover and watch them at feeding.
    • Your 80 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond 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)
    • Wels Catfish (300 cm) is big enough to swallow the 7 cm Bright Diamond Tetra whole.
    • Wels Catfish clearly outsizes Bright Diamond Tetra and is aggressive; risky unless the tank is big and well-planted.
    • Your 80 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond 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)
    • Size gap is too large (72 vs 7 cm): Wolf Cichlid will treat Bright Diamond Tetra as food.
    • pH preferences only just meet (Bright Diamond Tetra 5.5–6.8 vs Wolf Cichlid 7–8) — target the overlap and acclimate slowly.
    • Wolf Cichlid clearly outsizes Bright Diamond Tetra and is aggressive; risky unless the tank is big and well-planted.
    • Your 80 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
    • Keep Bright Diamond 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 bright diamond tetra community tank

Give the group a stable, planted 80 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 bright diamond tetra

As a peaceful species, bright 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.

Bright Diamond Tetra grows to about 7 cm, so avoid tank mates small enough to be seen as food — as a rule of thumb, skip anything under roughly 4 cm. Match its water, too: aim for 24–28 °C (75–82 °F), pH 5.5–6.8 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.

Bright Diamond 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 bright diamond tetra live with other fish?

Yes — with the right companions. Our checker finds 149 compatible freshwater species for bright 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 bright diamond tetra?

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

What fish should you avoid keeping with a bright 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 bright diamond tetra tank mates need?

Start from Bright Diamond Tetra's own minimum and scale up with every addition. The checker above defaults to a 80 L community tank and flags pairings that need more room — drag the slider to match your setup.

← Back to the full Bright Diamond Tetra care guide