Rainbow Emperor Tetra Tank Mates

Rainbow Emperor Tetra is semi-aggressive, so its tank mates need choosing with care. Here are the 97 freshwater species that pair well with a rainbow emperor tetra — plus the 96 to avoid — with a live checker you can tune to your own tank.

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

The best tank mates for a rainbow emperor tetra

  • 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.
  • Assassin Snail ✅ Compatible
    Easy care · Peaceful · 3 cm · 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.
  • Cherry Shrimp ✅ Compatible
    Easy care · Peaceful · 3 cm · 18–28 °C (64–82 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
  • Malaysian Trumpet Snail ✅ Compatible
    Easy care · Peaceful · 3 cm · 21–27 °C (70–81 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–27 °C — no size, zone or temperament conflicts.
  • Blue Danio ✅ Compatible
    Easy care · Peaceful · 4 cm · 21–26 °C (70–79 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, 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)
    Semi-aggressive + Peaceful, but with no direct clash here; 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.
  • Ghost Shrimp ✅ Compatible
    Easy care · Peaceful · 4 cm · 18–28 °C (64–82 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
  • Glowlight 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.
  • 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)
    Semi-aggressive + Peaceful, but with no direct clash here; 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)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
  • Yellow Phantom Tetra ✅ Compatible
    Easy care · Peaceful · 4 cm · 23–27 °C (73–81 °F)
    Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Black Phantom Tetra ✅ Compatible
    Easy care · Peaceful · 4.5 cm · 22–28 °C (72–82 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
  • Gold Tetra ✅ Compatible
    Easy care · Peaceful · 4.5 cm · 23–28 °C (73–82 °F)
    Semi-aggressive + Peaceful, but with no direct clash here; 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)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
  • X-ray Tetra ✅ Compatible
    Easy care · Peaceful · 4.5 cm · 22–28 °C (72–82 °F)
    Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Yellow Tetra ✅ Compatible
    Easy care · Peaceful · 4.5 cm · 20–25 °C (68–77 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–25 °C — no size, zone or temperament conflicts.
  • Amano Shrimp ✅ Compatible
    Easy care · Peaceful · 5 cm · 18–28 °C (64–82 °F)
    Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
  • Axelrod's Cory ✅ Compatible
    Easy care · Peaceful · 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.
  • Bandit Corydoras ✅ Compatible
    Easy care · Peaceful · 5 cm · 22–27 °C (72–81 °F)
    Compatible on the things that matter: shared water near 22–27 °C, workable temperaments, and no predator-and-prey size gap.
  • Checkered Barb ✅ Compatible
    Easy care · Peaceful · 5 cm · 20–25 °C (68–77 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–25 °C — no size, zone or temperament conflicts.
  • Cherry Barb ✅ Compatible
    Easy care · Peaceful · 5 cm · 23–27 °C (73–81 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 23–27 °C — no size, zone or temperament conflicts.
With caution

Rainbow Emperor 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)
    Rainbow Emperor Tetra and African Butterfly Cichlid can both be territorial; doable with space and dense planting, but watch for chasing.
  • 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)
    Rainbow Emperor Tetra and Angelfish can both be territorial; doable with space and dense planting, but watch for chasing.
  • Ash Lipped Apisto ⚠️ With caution
    Hard care · Semi-aggressive · 7 cm · 24–29 °C (75–84 °F)
    Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
  • Badis ⚠️ With caution
    Medium care · Semi-aggressive · 8 cm · 22–28 °C (72–82 °F)
    Rainbow Emperor Tetra and Badis can both be territorial; doable with space and dense planting, but watch for chasing.
  • Bamboo Shrimp ⚠️ With caution
    Medium care · Peaceful · 8 cm · 22–27 °C (72–81 °F)
    Rainbow Emperor Tetra is a notorious fin-nipper — even though Bamboo Shrimp is larger, an active shoal will harass its trailing fins. Only safe in a full group of 8+ with plenty of cover.
  • Banded Dwarf Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 7 cm · 24–30 °C (75–86 °F)
    Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
  • Banded Gourami ⚠️ With caution
    Easy care · Semi-aggressive · 12 cm · 22–28 °C (72–82 °F)
    Rainbow Emperor Tetra and Banded Gourami can both be territorial; doable with space and dense planting, but watch for chasing.

+ 139 more “with caution” pairings — see the interactive checker above.

Avoid

Fish to avoid keeping with a rainbow emperor tetra

  • Wels Catfish ⛔ Avoid
    Hard care · Aggressive · 300 cm · 15–25 °C (59–77 °F)
    Rainbow Emperor Tetra and Wels Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
  • Alligator Gar ⛔ Avoid
    Hard care · Aggressive · 250 cm · 24–28 °C (75–82 °F)
    Rainbow Emperor Tetra and Alligator Gar are both territorial and at least one is outright aggressive — expect serious fighting.
  • Redtail Catfish ⛔ Avoid
    Hard care · Aggressive · 120 cm · 24–27 °C (75–81 °F)
    Rainbow Emperor Tetra and Redtail Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
  • Fire Eel ⛔ Avoid
    Medium care · Semi-aggressive · 100 cm · 24–28 °C (75–82 °F)
    Rainbow Emperor 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)
    Two assertive fish, one genuinely aggressive: Rainbow Emperor Tetra and Clown Knifefish will hold territory and clash.
  • Koi ⛔ Avoid
    Medium care · Peaceful · 90 cm · 4–28 °C (39–82 °F)
    Rainbow Emperor Tetra is bite-sized to a 90 cm koi — it will be eaten.
  • Spotted Gar ⛔ Avoid
    Hard care · Aggressive · 90 cm · 18–26 °C (64–79 °F)
    Rainbow Emperor Tetra and Spotted Gar are both territorial and at least one is outright aggressive — expect serious fighting.
  • Wolf Cichlid ⛔ Avoid
    Hard care · Aggressive · 72 cm · 24–30 °C (75–86 °F)
    Two assertive fish, one genuinely aggressive: Rainbow Emperor Tetra and Wolf Cichlid will hold territory and clash.

+ 88 more to avoid — the checker above flags every one.

Interactive tool

Check any fish against a rainbow emperor tetra

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

Tank-mate checker

Will it live with a Rainbow Emperor Tetra?

We compare each fish against your rainbow emperor 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)
    • Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Amapá Tetra✅ Compatible
    Peaceful · 4 cm · Medium care · 24–27 °C (75–81 °F)
    • Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–27 °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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Amapá Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Assassin Snail✅ Compatible
    Peaceful · 3 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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Blue Danio✅ Compatible
    Peaceful · 4 cm · Easy care · 21–26 °C (70–79 °F)
    • Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °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 Rainbow Emperor Tetra in a shoal of 8+ 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)
    • Semi-aggressive + Peaceful, but with no direct clash here; 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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Blue Emperor Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Cardinal Tetra✅ Compatible
    Peaceful · 4 cm · Medium care · 23–27 °C (73–81 °F)
    • Semi-aggressive + Peaceful, 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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Cardinal 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)
    • Semi-aggressive + Peaceful, but with no direct clash here; 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 Rainbow Emperor Tetra in a shoal of 8+ 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 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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Flame Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Ghost Shrimp✅ Compatible
    Peaceful · 4 cm · Easy care · 18–28 °C (64–82 °F)
    • Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Ghost Shrimp 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)
    • 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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Glowlight 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)
    • Compatible on the things that matter: shared water near 22–24 °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 Rainbow Emperor Tetra in a shoal of 8+ 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)
    • Semi-aggressive + Peaceful, but with no direct clash here; 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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Jelly Bean Tetra in a shoal of 10+ or it gets stressed and nippy.
  • Marbled Hatchetfish✅ Compatible
    Peaceful · 4 cm · Medium care · 23–28 °C (73–82 °F)
    • Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ 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)
    • Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ 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)
    • Semi-aggressive + Peaceful, but with no direct clash here; 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 Rainbow Emperor Tetra in a shoal of 8+ 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)
    • Semi-aggressive + Peaceful, but with no direct clash here; 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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Purple 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 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 Rainbow Emperor Tetra in a shoal of 8+ 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)
    • Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–28 °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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Rosy Tetra in a shoal of 6+ or it gets stressed and nippy.
  • Rummy Nose Rasbora✅ Compatible
    Peaceful · 4 cm · Medium care · 20–26 °C (68–79 °F)
    • Semi-aggressive + Peaceful, but with no direct clash here; 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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Rummy Nose Rasbora in a shoal of 8+ or it gets stressed and nippy.
  • Sparkling Gourami✅ Compatible
    Peaceful · 4 cm · Medium care · 24–28 °C (75–82 °F)
    • Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Tailspotted Oto✅ Compatible
    Peaceful · 3.5 cm · Medium care · 22–27 °C (72–81 °F)
    • Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–27 °C — no size, zone or temperament conflicts.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Tailspotted Oto 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)
    • Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ 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)
    • Semi-aggressive + Peaceful, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ 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)
    • Semi-aggressive + Peaceful, but with no direct clash here; 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 Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Yellow Phantom 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)
    • Rainbow Emperor Tetra and Black Darter Tetra can both be territorial; doable with space and dense planting, but watch for chasing.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Blackwing Hatchetfish⚠️ With caution
    Peaceful · 3.5 cm · Medium care · 23–28 °C (73–82 °F)
    • Rainbow Emperor Tetra and Blackwing Hatchetfish are close in size, but the semi-aggressive one tends to dominate — add blackwing hatchetfish in a group to spread the pressure.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Blackwing Hatchetfish in a shoal of 6+ or it gets stressed and nippy.
  • Clown Killifish⚠️ With caution
    Peaceful · 3.5 cm · Medium care · 22–26 °C (72–79 °F)
    • Rainbow Emperor Tetra and Clown Killifish are close in size, but the semi-aggressive one tends to dominate — add clown killifish in a group to spread the pressure.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Clown Killifish in a shoal of 6+ or it gets stressed and nippy.
  • Crimson Red Betta⚠️ With caution
    Peaceful · 3.5 cm · Hard care · 24–29 °C (75–84 °F)
    • Rainbow Emperor Tetra is semi-aggressive and may chase or nip the smaller Crimson Red Betta — plant heavily and break up sight lines.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Endler's Livebearer⚠️ With caution
    Peaceful · 3 cm · Easy care · 22–28 °C (72–82 °F)
    • Expect Rainbow Emperor Tetra to harass Endler's Livebearer at times; give dense cover and watch them at feeding.
    • Keep Rainbow Emperor 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.
  • Eyespot Rasbora⚠️ With caution
    Peaceful · 3.5 cm · Medium care · 20–25 °C (68–77 °F)
    • Expect Rainbow Emperor Tetra to harass Eyespot Rasbora at times; give dense cover and watch them at feeding.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Eyespot Rasbora in a shoal of 8+ or it gets stressed and nippy.
  • Fire Red Licorice Gourami⚠️ With caution
    Peaceful · 3.5 cm · Hard care · 23–28 °C (73–82 °F)
    • Rainbow Emperor Tetra and Fire Red Licorice Gourami are close in size, but the semi-aggressive one tends to dominate — add fire red licorice gourami in a group to spread the pressure.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Glowlight Danio⚠️ With caution
    Peaceful · 3 cm · Easy care · 22–26 °C (72–79 °F)
    • Rainbow Emperor Tetra is semi-aggressive and may chase or nip the smaller Glowlight Danio — plant heavily and break up sight lines.
    • Keep Rainbow Emperor 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.
  • Glowlight Rasbora⚠️ With caution
    Peaceful · 3.5 cm · Easy care · 23–28 °C (73–82 °F)
    • Expect Rainbow Emperor Tetra to harass Glowlight Rasbora at times; give dense cover and watch them at feeding.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Glowlight Rasbora in a shoal of 8+ or it gets stressed and nippy.
  • Gold Ring Danio⚠️ With caution
    Peaceful · 3 cm · Easy care · 18–26 °C (64–79 °F)
    • Expect Rainbow Emperor Tetra to harass Gold Ring Danio at times; give dense cover and watch them at feeding.
    • Keep Rainbow Emperor 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.
  • Lambchop Rasbora⚠️ With caution
    Peaceful · 3 cm · Medium care · 23–28 °C (73–82 °F)
    • Rainbow Emperor Tetra and Lambchop Rasbora are close in size, but the semi-aggressive one tends to dominate — add lambchop rasbora in a group to spread the pressure.
    • Keep Rainbow Emperor 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.
  • Northern Glowlight Danio⚠️ With caution
    Peaceful · 3.5 cm · Medium care · 18–24 °C (64–75 °F)
    • Rainbow Emperor Tetra is semi-aggressive and may chase or nip the smaller Northern Glowlight Danio — plant heavily and break up sight lines.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Northern Glowlight Danio in a shoal of 8+ or it gets stressed and nippy.
  • Pygmy Corydoras⚠️ With caution
    Peaceful · 3.2 cm · Easy care · 22–26 °C (72–79 °F)
    • Rainbow Emperor Tetra is semi-aggressive and may chase or nip the smaller Pygmy Corydoras — plant heavily and break up sight lines.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
    • Keep Pygmy Corydoras 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)
    • Rainbow Emperor Tetra and Serpae Tetra can both be territorial; doable with space and dense planting, but watch for chasing.
    • Keep Rainbow Emperor 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.
  • Strawberry Betta⚠️ With caution
    Peaceful · 4 cm · Medium care · 22–27 °C (72–81 °F)
    • Rainbow Emperor Tetra is a notorious fin-nipper — even though Strawberry Betta is larger, an active shoal will harass its trailing fins. Only safe in a full group of 8+ with plenty of cover.
    • Keep Rainbow Emperor Tetra in a shoal of 8+ or it gets stressed and nippy.
  • Tiger Badis⚠️ With caution
    Semi-aggressive · 4 cm · Medium care · 22–24 °C (72–75 °F)
    • Rainbow Emperor Tetra and Tiger Badis can both be territorial; doable with space and dense planting, but watch for chasing.
    • Keep Rainbow Emperor 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)
    • Rainbow Emperor Tetra and Alligator Gar are both territorial and at least one is outright aggressive — expect serious fighting.
    • Size gap is too large (250 vs 3.6 cm): Alligator Gar will treat Rainbow Emperor Tetra as food.
    • Rainbow Emperor Tetra is a notorious fin-nipper — even though Alligator Gar is larger, an active shoal will harass its trailing fins. Only safe in a full group of 8+ with plenty of cover.
    • Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
    • Keep Rainbow Emperor 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)
    • Two assertive fish, one genuinely aggressive: Rainbow Emperor Tetra and Clown Knifefish will hold territory and clash.
    • Rainbow Emperor Tetra is bite-sized to a 90 cm predatory clown knifefish — it will be eaten.
    • Your 75 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
    • Keep Rainbow Emperor 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)
    • Rainbow Emperor Tetra is bite-sized to a 100 cm predatory fire eel — it will be eaten.
    • Rainbow Emperor Tetra and Fire Eel can both be territorial; doable with space and dense planting, but watch for chasing.
    • Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
    • Keep Rainbow Emperor 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)
    • Rainbow Emperor Tetra is bite-sized to a 90 cm koi — it will be eaten.
    • Koi is slow and long-finned; a busy rainbow emperor tetra shoal tends to nip at it. Keep rainbow emperor tetra in a proper group of 8+ and watch them closely.
    • Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
    • Keep Rainbow Emperor 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)
    • Rainbow Emperor Tetra and Redtail Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
    • Redtail Catfish (120 cm) is big enough to swallow the 3.6 cm Rainbow Emperor Tetra whole.
    • Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
    • Keep Rainbow Emperor 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)
    • Rainbow Emperor Tetra and Spotted Gar are both territorial and at least one is outright aggressive — expect serious fighting.
    • Rainbow Emperor Tetra is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
    • Rainbow Emperor Tetra is a notorious fin-nipper — even though Spotted Gar is larger, an active shoal will harass its trailing fins. Only safe in a full group of 8+ with plenty of cover.
    • Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
    • Keep Rainbow Emperor 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)
    • Rainbow Emperor Tetra and Wels Catfish are both territorial and at least one is outright aggressive — expect serious fighting.
    • Size gap is too large (300 vs 3.6 cm): Wels Catfish will treat Rainbow Emperor Tetra as food.
    • Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
    • Keep Rainbow Emperor 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)
    • Two assertive fish, one genuinely aggressive: Rainbow Emperor Tetra and Wolf Cichlid will hold territory and clash.
    • Wolf Cichlid (72 cm) is big enough to swallow the 3.6 cm Rainbow Emperor Tetra whole.
    • Wolf Cichlid is slow and long-finned; a busy rainbow emperor tetra shoal tends to nip at it. Keep rainbow emperor tetra in a proper group of 8+ and watch them closely.
    • Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
    • Keep Rainbow Emperor 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 rainbow emperor 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 rainbow emperor tetra

Being semi-aggressive, rainbow emperor tetra can nip or harass smaller, slower or long-finned fish — give it space, broken sight-lines and similarly robust companions. It mostly occupies the middle of the tank, so it pairs naturally with species that use the other levels.

Rainbow Emperor Tetra grows to about 3.6 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 22–28 °C (72–82 °F), pH 6–7.5 and 2–15 dGH. Fish needing very different conditions — coldwater species, or hard-water lovers against a soft-water fish — rarely thrive side by side.

Rainbow Emperor 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 rainbow emperor tetra live with other fish?

Yes — with the right companions. Our checker finds 97 compatible freshwater species for rainbow emperor 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 rainbow emperor tetra?

Easy, peaceful, similarly-sized species top the list — for example Red Lip Nerite Snail, Assassin Snail, Cherry Shrimp. Use the checker above to match against your own tank size.

What fish should you avoid keeping with a rainbow emperor 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 rainbow emperor tetra tank mates need?

Start from Rainbow Emperor 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 Rainbow Emperor Tetra care guide