Cardinal Tetra Tank Mates

Cardinal Tetra is peaceful, so its tank mates need choosing with care. Here are the 124 freshwater species that pair well with a cardinal tetra — plus the 83 to avoid — with a live checker you can tune to your own tank.

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

The best tank mates for a cardinal 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 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 23–27 °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)
    Both are peaceful, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
  • Dawn Tetra ✅ Compatible
    Easy care · Peaceful · 2.5 cm · 22–28 °C (72–82 °F)
    Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
  • 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)
    Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
  • Neon Tetra ✅ Compatible
    Easy care · Peaceful · 3 cm · 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.
  • Tail-spot Corydoras ✅ Compatible
    Easy care · Peaceful · 3 cm · 22–28 °C (72–82 °F)
    Both are peaceful, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
  • 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 23–26 °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)
    Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
  • Blue Danio ✅ Compatible
    Easy care · Peaceful · 4 cm · 21–26 °C (70–79 °F)
    Compatible on the things that matter: shared water near 23–26 °C, workable temperaments, and no predator-and-prey size gap.
  • 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 23–27 °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 23–27 °C — no size, zone or temperament conflicts.
  • Golden Dwarf Barb ✅ Compatible
    Easy care · Peaceful · 4 cm · 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.
  • Phoenix Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 23–28 °C (73–82 °F)
    Compatible on the things that matter: shared water near 23–27 °C, workable temperaments, and no predator-and-prey size gap.
  • Red Phantom Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 22–28 °C (72–82 °F)
    Compatible on the things that matter: shared water near 23–27 °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, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
  • Yellow Phantom Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 23–27 °C (73–81 °F)
    Both are peaceful, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
  • Black Phantom Tetra ✅ Compatible
    Easy care · Peaceful · 4.5 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.
  • Gold Tetra ✅ Compatible
    Easy care · Peaceful · 4.5 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.
  • Lemon Tetra ✅ Compatible
    Easy care · Peaceful · 4.5 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.
With caution

Cardinal 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 Cardinal Tetra at times; give dense cover and watch them at feeding.
  • Agassiz's Dwarf Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 9 cm · 24–30 °C (75–86 °F)
    Agassiz's Dwarf Cichlid is semi-aggressive and may chase or nip the smaller Cardinal Tetra — plant heavily and break up sight lines.
  • 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 Cardinal Tetra and is semi-aggressive; risky unless the tank is big and well-planted.
  • Ash Lipped Apisto ⚠️ With caution
    Hard care · Semi-aggressive · 7 cm · 24–29 °C (75–84 °F)
    Ash Lipped Apisto is semi-aggressive and may chase or nip the smaller Cardinal Tetra — plant heavily and break up sight lines.
  • Assassin Snail ⚠️ With caution
    Easy care · Peaceful · 3 cm · 22–26 °C (72–79 °F)
    Water hardness preferences differ (Cardinal Tetra 1–6 vs Assassin Snail 8–20 dGH).
  • Auratus Cichlid ⚠️ With caution
    Medium care · Aggressive · 11 cm · 23–28 °C (73–82 °F)
    pH preferences only just meet (Cardinal Tetra 4.5–7 vs Auratus Cichlid 7.6–8.8) — target the overlap and acclimate slowly.
  • Badis ⚠️ With caution
    Medium care · Semi-aggressive · 8 cm · 22–28 °C (72–82 °F)
    Badis clearly outsizes Cardinal Tetra and is semi-aggressive; risky unless the tank is big and well-planted.

+ 125 more “with caution” pairings — see the interactive checker above.

Avoid

Fish to avoid keeping with a cardinal tetra

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

+ 75 more to avoid — the checker above flags every one.

Interactive tool

Check any fish against a cardinal tetra

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

Tank-mate checker

Will it live with a Cardinal Tetra?

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

  • African Dwarf Frog✅ Compatible
    Peaceful · 4 cm · Medium 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.
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Amapá Tetra✅ Compatible
    Peaceful · 4 cm · Medium care · 24–27 °C (75–81 °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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Amapá Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Black Phantom Tetra✅ Compatible
    Peaceful · 4.5 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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Black Phantom Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Blue Danio✅ Compatible
    Peaceful · 4 cm · Easy care · 21–26 °C (70–79 °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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Blue Danio in a shoal of 6+ or it gets stressed and nippy.
  • Blue Emperor Tetra✅ Compatible
    Peaceful · 4 cm · Medium care · 23–27 °C (73–81 °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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Blue Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Emperor Tetra✅ Compatible
    Peaceful · 4 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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Flame Tetra✅ Compatible
    Peaceful · 4 cm · Easy care · 22–28 °C (72–82 °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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Flame Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Glowlight Tetra✅ Compatible
    Peaceful · 4 cm · Easy care · 22–28 °C (72–82 °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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Glowlight Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Gold Tetra✅ Compatible
    Peaceful · 4.5 cm · Easy 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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Gold Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Golden Dwarf Barb✅ Compatible
    Peaceful · 4 cm · Easy 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.
    • Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Golden Dwarf Barb in a shoal of 6+ or it gets stressed and nippy.
  • Jelly Bean Tetra✅ Compatible
    Peaceful · 4 cm · Medium care · 20–26 °C (68–79 °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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Jelly Bean Tetra in a shoal of 10+ or it gets stressed and nippy.
  • Lemon Tetra✅ Compatible
    Peaceful · 4.5 cm · Easy 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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Lemon Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Marbled Hatchetfish✅ Compatible
    Peaceful · 4 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.
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Marbled Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
  • Otocinclus✅ Compatible
    Peaceful · 4 cm · Medium care · 21–26 °C (70–79 °F)
    • Both are peaceful, and their water overlaps around 23–26 °C — no size, zone or temperament conflicts.
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Otocinclus in a shoal of 6+ or it gets stressed and nippy.
  • Phoenix Tetra✅ Compatible
    Peaceful · 4 cm · Easy care · 23–28 °C (73–82 °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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Phoenix Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Purple Tetra✅ Compatible
    Peaceful · 4 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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Purple Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Rainbow Emperor Tetra✅ Compatible
    Semi-aggressive · 3.6 cm · Medium care · 22–28 °C (72–82 °F)
    • Peaceful + Semi-aggressive, but with no direct clash here, 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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Red Phantom Tetra✅ Compatible
    Peaceful · 4 cm · Easy care · 22–28 °C (72–82 °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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Red Phantom Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Rosy Tetra✅ Compatible
    Peaceful · 4 cm · Easy care · 22–28 °C (72–82 °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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Rosy Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Sparkling Gourami✅ Compatible
    Peaceful · 4 cm · Medium care · 24–28 °C (75–82 °F)
    • Both are peaceful, and their water overlaps around 24–27 °C — no size, zone or temperament conflicts.
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Strawberry Betta✅ Compatible
    Peaceful · 4 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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Threadfin Rainbowfish✅ Compatible
    Peaceful · 4 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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Threadfin Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
  • Tiger Otocinclus✅ Compatible
    Peaceful · 4 cm · Medium care · 22–27 °C (72–81 °F)
    • Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Tiger Otocinclus in a shoal of 6+ or it gets stressed and nippy.
  • Yellow Phantom Tetra✅ Compatible
    Peaceful · 4 cm · Easy care · 23–27 °C (73–81 °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 Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Yellow Phantom Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Assassin Snail⚠️ With caution
    Peaceful · 3 cm · Easy care · 22–26 °C (72–79 °F)
    • Water hardness preferences differ (Cardinal Tetra 1–6 vs Assassin Snail 8–20 dGH).
    • Keep Cardinal Tetra in a shoal of 6+ 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 and Cardinal Tetra are close in size, but the semi-aggressive one tends to dominate — add cardinal tetra in a group to spread the pressure.
    • Keep Cardinal 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 (4.5–7 vs 7.5–8.5); doable if you sit in the shared band, but not ideal long-term.
    • Water hardness preferences differ (Cardinal Tetra 1–6 vs Blue Turbo Snail 8–18 dGH).
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Cherry Shrimp⚠️ With caution
    Peaceful · 3 cm · Easy care · 18–28 °C (64–82 °F)
    • Adult Cherry Shrimp might survive with Cardinal Tetra, but expect the young to be eaten — plant heavily.
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Cherry Shrimp in a shoal of 10+ 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 (Cardinal Tetra 1–6 vs Endler's Livebearer 10–25 dGH).
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Endler's Livebearer in a shoal of 6+ or it gets stressed and nippy.
  • Ghost Shrimp⚠️ With caution
    Peaceful · 4 cm · Easy care · 18–28 °C (64–82 °F)
    • Adult Ghost Shrimp might survive with Cardinal Tetra, but expect the young to be eaten — plant heavily.
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Ghost Shrimp 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 Cardinal Tetra — plant heavily and break up sight lines.
    • Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
    • Keep Cardinal Tetra 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 Cardinal Tetra 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.
  • Mystery Snail⚠️ With caution
    Peaceful · 5 cm · Easy care · 20–28 °C (68–82 °F)
    • Water hardness preferences differ (Cardinal Tetra 1–6 vs Mystery Snail 7–18 dGH).
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Rummy Nose Rasbora⚠️ With caution
    Peaceful · 4 cm · Medium care · 20–26 °C (68–79 °F)
    • Water hardness preferences differ (Cardinal Tetra 1–6 vs Rummy Nose Rasbora 8–16 dGH).
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
    • Keep Rummy Nose Rasbora 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 Cardinal Tetra — plant heavily and break up sight lines.
    • Keep Cardinal Tetra in a shoal of 6+ 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)
    • Silvertip Tetra is semi-aggressive and may chase or nip the smaller Cardinal Tetra — plant heavily and break up sight lines.
    • Keep Cardinal Tetra 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 and Cardinal Tetra are close in size, but the semi-aggressive one tends to dominate — add cardinal tetra in a group to spread the pressure.
    • Keep Cardinal Tetra 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 is aggressive and may chase or nip the smaller Cardinal Tetra — plant heavily and break up sight lines.
    • Keep Cardinal 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)
    • Tiger Badis is semi-aggressive and may chase or nip the smaller Cardinal Tetra — plant heavily and break up sight lines.
    • Keep Cardinal Tetra 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)
    • Expect Wine Red Betta to harass Cardinal Tetra at times; give dense cover and watch them at feeding.
    • Keep Cardinal 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)
    • Cardinal Tetra is bite-sized to a 250 cm predatory alligator gar — it will be eaten.
    • Alligator Gar clearly outsizes Cardinal Tetra and is aggressive; risky unless the tank is big and well-planted.
    • Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
    • Keep Cardinal Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Clown Knifefish⛔ Not recommended
    Aggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
    • Clown Knifefish (90 cm) is big enough to swallow the 4 cm Cardinal Tetra whole.
    • Clown Knifefish is aggressive and may chase or nip the smaller Cardinal 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 Cardinal 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)
    • Fire Eel (100 cm) is big enough to swallow the 4 cm Cardinal Tetra whole.
    • Expect Fire Eel to harass Cardinal 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 Cardinal 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 4 cm Cardinal Tetra whole.
    • Water hardness preferences differ (Cardinal Tetra 1–6 vs Koi 9–18 dGH).
    • Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
    • Keep Cardinal 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)
    • Cardinal 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 Cardinal 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 Cardinal 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 4 cm): Spotted Gar will treat Cardinal Tetra as food.
    • Spotted Gar clearly outsizes Cardinal 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 Cardinal 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 4 cm): Wels Catfish will treat Cardinal Tetra as food.
    • Wels Catfish is aggressive and may chase or nip the smaller Cardinal Tetra — plant heavily and break up sight lines.
    • Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
    • Keep Cardinal 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)
    • Cardinal Tetra is bite-sized to a 72 cm predatory wolf cichlid — it will be eaten.
    • Water hardness preferences differ (Cardinal Tetra 1–6 vs Wolf Cichlid 8–20 dGH).
    • Wolf Cichlid clearly outsizes Cardinal Tetra and is aggressive; risky unless the tank is big and well-planted.
    • Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
    • Keep Cardinal 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 cardinal 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 cardinal tetra

As a peaceful species, cardinal 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.

Cardinal Tetra grows to about 4 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 23–27 °C (73–81 °F), pH 4.5–7 and 1–6 dGH. Fish needing very different conditions — coldwater species, or hard-water lovers against a soft-water fish — rarely thrive side by side.

Cardinal 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 cardinal tetra live with other fish?

Yes — with the right companions. Our checker finds 124 compatible freshwater species for cardinal 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 cardinal 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 cardinal 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 cardinal tetra tank mates need?

Start from Cardinal 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 Cardinal Tetra care guide