Swordtail Tank Mates

Swordtail is semi-aggressive, so its tank mates need choosing with care. Here are the 15 freshwater species that pair well with a swordtail — plus the 63 to avoid — with a live checker you can tune to your own tank.

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

The best tank mates for a swordtail

  • Agassiz's Corydoras ✅ Compatible
    Easy care · Peaceful · 6 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.
  • Elegant Cory ✅ Compatible
    Easy care · Peaceful · 6 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.
  • False Julii Corydoras ✅ Compatible
    Easy care · Peaceful · 6 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.
  • Corydoras Catfish ✅ Compatible
    Easy care · Peaceful · 6.5 cm · 22–26 °C (72–79 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
  • Spotfin Corydoras ✅ Compatible
    Easy care · Peaceful · 6.5 cm · 22–26 °C (72–79 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
  • Peppered Corydoras ✅ Compatible
    Easy care · Peaceful · 7 cm · 18–26 °C (64–79 °F)
    Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
  • Spotted Corydoras ✅ Compatible
    Easy care · Peaceful · 7 cm · 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.
  • Burmese Loach ✅ Compatible
    Easy care · Peaceful · 9 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.
  • Blood Red Tiger Pleco ✅ Compatible
    Medium care · Peaceful · 6 cm · 24–29 °C (75–84 °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.
  • Slate Corydoras ✅ Compatible
    Medium care · Peaceful · 6 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.
  • Sterbai Corydoras ✅ Compatible
    Medium care · Peaceful · 6.5 cm · 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.
  • Bolivian Ram ✅ Compatible
    Medium care · Peaceful · 8 cm · 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.
  • Leopard Frog Pleco ✅ Compatible
    Medium care · Peaceful · 9 cm · 25–30 °C (77–86 °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.
  • Spotted Rubbernose Pleco ✅ Compatible
    Medium care · Peaceful · 12 cm · 20–26 °C (68–79 °F)
    Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
  • Banjo Catfish ✅ Compatible
    Medium care · Peaceful · 15 cm · 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.
With caution

Swordtail tank mates that can work with care

  • Adolf's Cory ⚠️ With caution
    Medium care · Peaceful · 5.5 cm · 22–26 °C (72–79 °F)
    Water hardness preferences differ (Swordtail 12–25 vs Adolf's Cory 1–8 dGH).
  • Afra Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 10 cm · 24–28 °C (75–82 °F)
    Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
  • African Butterfly Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 8 cm · 22–28 °C (72–82 °F)
    Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
  • African Dwarf Frog ⚠️ With caution
    Medium care · Peaceful · 4 cm · 22–26 °C (72–79 °F)
    African Dwarf Frog is small enough to tempt Swordtail; only risk it in a densely planted setup with hiding spots.
  • Agassiz's Dwarf Cichlid ⚠️ With caution
    Medium care · Semi-aggressive · 9 cm · 24–30 °C (75–86 °F)
    One likes softer water and the other harder (12–25 vs 0–8 dGH) — a compromise, not a perfect match.
  • Altifrons Geophagus ⚠️ With caution
    Medium care · Semi-aggressive · 25 cm · 24–28 °C (75–82 °F)
    One likes softer water and the other harder (12–25 vs 1–8 dGH) — a compromise, not a perfect match.
  • Amano Shrimp ⚠️ With caution
    Easy care · Peaceful · 5 cm · 18–28 °C (64–82 °F)
    Swordtail may eat Amano Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
  • Amapá Tetra ⚠️ With caution
    Medium care · Peaceful · 4 cm · 24–27 °C (75–81 °F)
    Water hardness preferences differ (Swordtail 12–25 vs Amapá Tetra 1–10 dGH).

+ 254 more “with caution” pairings — see the interactive checker above.

Avoid

Fish to avoid keeping with a swordtail

  • Wels Catfish ⛔ Avoid
    Hard care · Aggressive · 300 cm · 15–25 °C (59–77 °F)
    Two assertive fish, one genuinely aggressive: Swordtail and Wels Catfish will hold territory and clash.
  • Alligator Gar ⛔ Avoid
    Hard care · Aggressive · 250 cm · 24–28 °C (75–82 °F)
    Two assertive fish, one genuinely aggressive: Swordtail and Alligator Gar will hold territory and clash.
  • Redtail Catfish ⛔ Avoid
    Hard care · Aggressive · 120 cm · 24–27 °C (75–81 °F)
    Two assertive fish, one genuinely aggressive: Swordtail and Redtail Catfish will hold territory and clash.
  • 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 14 cm Swordtail whole.
  • Clown Knifefish ⛔ Avoid
    Hard care · Aggressive · 90 cm · 24–28 °C (75–82 °F)
    Swordtail and Clown Knifefish are both territorial and at least one is outright aggressive — expect serious fighting.
  • Koi ⛔ Avoid
    Medium care · Peaceful · 90 cm · 4–28 °C (39–82 °F)
    Swordtail 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)
    Two assertive fish, one genuinely aggressive: Swordtail and Spotted Gar will hold territory and clash.
  • Wolf Cichlid ⛔ Avoid
    Hard care · Aggressive · 72 cm · 24–30 °C (75–86 °F)
    Swordtail and Wolf Cichlid are both territorial and at least one is outright aggressive — expect serious fighting.

+ 55 more to avoid — the checker above flags every one.

Interactive tool

Check any fish against a swordtail

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

Tank-mate checker

Will it live with a Swordtail?

We compare each fish against your swordtail 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)
    • 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 Agassiz's Corydoras in a shoal of 6+ or it gets stressed and nippy.
  • Banjo Catfish✅ Compatible
    Peaceful · 15 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.
  • Blood Red Tiger Pleco✅ Compatible
    Peaceful · 6 cm · Medium care · 24–29 °C (75–84 °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.
  • Bolivian Ram✅ Compatible
    Peaceful · 8 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.
  • Burmese Loach✅ Compatible
    Peaceful · 9 cm · Easy care · 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.
  • Corydoras Catfish✅ Compatible
    Peaceful · 6.5 cm · Easy care · 22–26 °C (72–79 °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 Corydoras Catfish in a shoal of 6+ or it gets stressed and nippy.
  • Elegant Cory✅ Compatible
    Peaceful · 6 cm · Easy care · 22–28 °C (72–82 °F)
    • Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Elegant Cory in a shoal of 6+ or it gets stressed and nippy.
  • False Julii Corydoras✅ Compatible
    Peaceful · 6 cm · Easy care · 22–26 °C (72–79 °F)
    • Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep False Julii Corydoras in a shoal of 6+ or it gets stressed and nippy.
  • Leopard Frog Pleco✅ Compatible
    Peaceful · 9 cm · Medium care · 25–30 °C (77–86 °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.
  • Peppered Corydoras✅ Compatible
    Peaceful · 7 cm · Easy care · 18–26 °C (64–79 °F)
    • Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Peppered Corydoras in a shoal of 6+ or it gets stressed and nippy.
  • Slate Corydoras✅ Compatible
    Peaceful · 6 cm · Medium care · 23–28 °C (73–82 °F)
    • Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
    • Keep Slate Corydoras in a shoal of 6+ or it gets stressed and nippy.
  • Spotfin Corydoras✅ Compatible
    Peaceful · 6.5 cm · Easy care · 22–26 °C (72–79 °F)
    • Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
    • 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)
    • 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 Spotted Corydoras in a shoal of 6+ or it gets stressed and nippy.
  • Spotted Rubbernose Pleco✅ Compatible
    Peaceful · 12 cm · Medium care · 20–26 °C (68–79 °F)
    • Semi-aggressive + Peaceful, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
  • 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 Sterbai Corydoras in a shoal of 6+ or it gets stressed and nippy.
  • Angelfish⚠️ With caution
    Semi-aggressive · 15 cm · Medium care · 24–30 °C (75–86 °F)
    • Water hardness preferences differ (Swordtail 12–25 vs Angelfish 3–10 dGH).
    • Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
    • Your 75 L tank is below the ~110 L this pairing really wants — crowding raises aggression.
  • Blue Flash Cichlid⚠️ With caution
    Semi-aggressive · 15 cm · Medium care · 24–28 °C (75–82 °F)
    • Swordtail and Blue Flash Cichlid can both be territorial; doable with space and dense planting, but watch for chasing.
    • Your 75 L tank is below the ~210 L this pairing really wants — crowding raises aggression.
  • Calvus Cichlid⚠️ With caution
    Semi-aggressive · 14 cm · Medium care · 24–27 °C (75–81 °F)
    • Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
    • Your 75 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
  • Clown Barb⚠️ With caution
    Semi-aggressive · 15 cm · Medium care · 24–30 °C (75–86 °F)
    • Different pH ranges (7–8.3 vs 6–6.5); doable if you sit in the shared band, but not ideal long-term.
    • Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
    • Your 75 L tank is below the ~132 L this pairing really wants — crowding raises aggression.
    • Keep Clown Barb in a shoal of 6+ or it gets stressed and nippy.
  • Denison Barb⚠️ With caution
    Peaceful · 15 cm · Medium care · 18–25 °C (64–77 °F)
    • Your 75 L tank is below the ~200 L this pairing really wants — crowding raises aggression.
    • Keep Denison Barb in a shoal of 6+ or it gets stressed and nippy.
  • Dolphin Cichlid⚠️ With caution
    Semi-aggressive · 15 cm · Medium care · 23–28 °C (73–82 °F)
    • Water hardness preferences differ (Swordtail 12–25 vs Dolphin Cichlid 2–10 dGH).
    • Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
    • Your 75 L tank is below the ~208 L this pairing really wants — crowding raises aggression.
  • Eureka Red Peacock Cichlid⚠️ With caution
    Semi-aggressive · 15 cm · Medium care · 24–28 °C (75–82 °F)
    • Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
    • Your 75 L tank is below the ~200 L this pairing really wants — crowding raises aggression.
  • Firemouth Cichlid⚠️ With caution
    Semi-aggressive · 15 cm · Medium care · 22–29 °C (72–84 °F)
    • Swordtail and Firemouth Cichlid can both be territorial; doable with space and dense planting, but watch for chasing.
    • Your 75 L tank is below the ~200 L this pairing really wants — crowding raises aggression.
  • Giant Glass Catfish⚠️ With caution
    Peaceful · 15 cm · Medium care · 22–27 °C (72–81 °F)
    • Your 75 L tank is below the ~120 L this pairing really wants — crowding raises aggression.
  • Gold Zebra Loach⚠️ With caution
    Semi-aggressive · 15 cm · Medium care · 25–29 °C (77–84 °F)
    • Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
    • Your 75 L tank is below the ~130 L this pairing really wants — crowding raises aggression.
  • Green Phantom Pleco⚠️ With caution
    Semi-aggressive · 15 cm · Medium care · 26–30 °C (79–86 °F)
    • Water hardness preferences differ (Swordtail 12–25 vs Green Phantom Pleco 1–10 dGH).
    • Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
    • Your 75 L tank is below the ~150 L this pairing really wants — crowding raises aggression.
  • Marbled Hoplo⚠️ With caution
    Peaceful · 14 cm · Easy care · 22–28 °C (72–82 °F)
    • Your 75 L tank is below the ~80 L this pairing really wants — crowding raises aggression.
  • Moonlight Gourami⚠️ With caution
    Peaceful · 15 cm · Easy care · 25–30 °C (77–86 °F)
    • Your 75 L tank is below the ~115 L this pairing really wants — crowding raises aggression.
  • Rainbow Cichlid⚠️ With caution
    Semi-aggressive · 14 cm · Easy care · 22–28 °C (72–82 °F)
    • Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
    • Your 75 L tank is below the ~130 L this pairing really wants — crowding raises aggression.
  • Spotted Talking Catfish⚠️ With caution
    Peaceful · 15 cm · Easy care · 22–26 °C (72–79 °F)
    • Your 75 L tank is below the ~110 L this pairing really wants — crowding raises aggression.
  • Yoyo Loach⚠️ With caution
    Semi-aggressive · 15 cm · Medium care · 24–30 °C (75–86 °F)
    • Swordtail and Yoyo Loach can both be territorial; doable with space and dense planting, but watch for chasing.
    • Your 75 L tank is below the ~115 L this pairing really wants — crowding raises aggression.
  • Alligator Gar⛔ Not recommended
    Aggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
    • Two assertive fish, one genuinely aggressive: Swordtail and Alligator Gar will hold territory and clash.
    • Alligator Gar (250 cm) is big enough to swallow the 14 cm Swordtail whole.
    • Your 75 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
  • Clown Knifefish⛔ Not recommended
    Aggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
    • Swordtail and Clown Knifefish are both territorial and at least one is outright aggressive — expect serious fighting.
    • Swordtail 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.
  • 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 14 cm Swordtail whole.
    • Both are a bit pushy (semi-aggressive + semi-aggressive) — workable only in a larger tank with cover and broken sight lines.
    • Your 75 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
  • Koi⛔ Not recommended
    Peaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
    • Swordtail is bite-sized to a 90 cm koi — it will be eaten.
    • Your 75 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
  • Redtail Catfish⛔ Not recommended
    Aggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
    • Two assertive fish, one genuinely aggressive: Swordtail and Redtail Catfish will hold territory and clash.
    • Swordtail is bite-sized to a 120 cm predatory redtail catfish — it will be eaten.
    • One likes softer water and the other harder (12–25 vs 3–10 dGH) — a compromise, not a perfect match.
    • Your 75 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
  • Spotted Gar⛔ Not recommended
    Aggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
    • Two assertive fish, one genuinely aggressive: Swordtail and Spotted Gar will hold territory and clash.
    • Size gap is too large (90 vs 14 cm): Spotted Gar will treat Swordtail as food.
    • Your 75 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
  • Wels Catfish⛔ Not recommended
    Aggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
    • Two assertive fish, one genuinely aggressive: Swordtail and Wels Catfish will hold territory and clash.
    • Swordtail is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
    • Your 75 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
  • Wolf Cichlid⛔ Not recommended
    Aggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
    • Swordtail and Wolf Cichlid are both territorial and at least one is outright aggressive — expect serious fighting.
    • Size gap is too large (72 vs 14 cm): Wolf Cichlid will treat Swordtail as food.
    • Your 75 L tank is below the ~760 L this pairing really wants — crowding raises aggression.

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 swordtail 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 swordtail

Being semi-aggressive, swordtail 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.

Swordtail grows to about 14 cm, so avoid tank mates small enough to be seen as food — as a rule of thumb, skip anything under roughly 7 cm. Match its water, too: aim for 22–28 °C (72–82 °F), pH 7–8.3 and 12–25 dGH. Fish needing very different conditions — coldwater species, or hard-water lovers against a soft-water fish — rarely thrive side by side.

Swordtail is a shoaling fish — stock a group of 3+ 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 swordtail live with other fish?

Yes — with the right companions. Our checker finds 15 compatible freshwater species for swordtail. 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 swordtail?

Easy, peaceful, similarly-sized species top the list — for example Agassiz's Corydoras, Elegant Cory, False Julii Corydoras. Use the checker above to match against your own tank size.

What fish should you avoid keeping with a swordtail?

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 swordtail tank mates need?

Start from Swordtail'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 Swordtail care guide