Swordtail Tank Mates

Swordtails are active, peaceful livebearers — bigger and stronger swimmers than platies, needing a longer tank.

They share the platy's easy-going temperament and broad compatibility, but males can squabble and the fish are strong jumpers, so a lid and a roomy footprint matter. The engine clears the usual peaceful community crowd.

Swordtail key facts

The sourced figures the engine uses to judge Swordtail pairings.

Top Swordtail tank mates

A ranked shortlist: the species the engine clears with Swordtail and that suit its size and temperament best — tap a name for its care guide, or use + Add to test the pairing in the planner.

No tank mates match these filters — try removing one. Reset filters

Other engine-cleared options (not necessarily ideal)

These clear TankStocking's hard welfare checks with Swordtail, but are larger, bolder, or otherwise less ideal than the shortlist above — read up before committing.

Possible with care

These can work, but the engine flags something to watch — read the reason before you commit.

• Betta (Siamese Fighting Fish) — Territorial
• Paradise Fish — Aggression
• Cockatoo Dwarf Cichlid (Apisto Cacatuoides) — Territorial
• Convict Cichlid — Aggression
• Firemouth Cichlid — Territorial
• Jewel Cichlid — Aggression
• Kribensis (Rainbow Krib) — Territorial
• Oscar — Aggression
• Golden Wonder Killifish (Striped Panchax) — Aggression
• Rainbow Shark — Aggression
• Redtail Black Shark — Aggression
• Pictus Catfish — Aggression

Best avoided

A hard welfare check fires for each of these — don't mix them with Swordtail.

• Chocolate Gourami — Species-only fish
• Licorice Gourami — Species-only fish
• Tinfoil Barb — Predation risk
• Discus — Temperature clash
• Green Severum — Predation risk
• Multifasciatus Shell-Dweller — Territorial, Species-only fish
• Common Goldfish — Coldwater + tropical
• Fancy Goldfish — Coldwater + tropical
• Gold White Cloud Mountain Minnow — Temperature clash, Coldwater + tropical
• Rosy Red Minnow (Fathead Minnow) — Coldwater + tropical
• White Cloud Mountain Minnow — Temperature clash, Coldwater + tropical
• Bumblebee Goby — Territorial, Species-only fish
• Dwarf Pufferfish (Pea Puffer) — Species-only fish
• Common Pleco — Predation risk

Keeping Swordtail well: the detail

Beyond the table — the behaviour, the parameters that actually move the needle, and the mistakes that cost fish. Hobbyist context, not a verdict; the planner above is what judges your plan.

Water parameters in practice

Swordtails share the platy's love of hard, alkaline water (GH 10–25 dGH, pH 7–8.3) but are bigger, stronger swimmers that need length and a tight lid — they are notorious jumpers. Keep 22–28 °C and give them a long footprint to cruise. The water chemistry is the easy part; the lid and the swimming room are what people forget.

Why Swordtail behaves the way it does

Swordtails come from the flowing, hard-water streams and rivers of Central America, which is why they are powerful, restless swimmers compared with the more sedate platy. The male's sword is a display and rivalry trait, and males will spar and chase. That river-fish energy is also behind the jumping — open water in the wild means a fish that bolts upward when startled.

Common Swordtail stocking mistakes

The first mistake is an open-topped or short tank: swordtails jump and they need length to swim, so a tall nano is wrong on both counts. The second is keeping multiple males without enough space or females, which leads to constant chasing. The third is the usual livebearer one — no plan for fry.

Early signs something is wrong

A swordtail that hangs near the surface gasping, clamps its fins, or stops cruising is signalling poor water or stress — they are active by nature, so stillness is the warning. Torn fins on males point to sparring; a missing fish points to a gap in the lid. Healthy swordtails patrol the length of the tank tirelessly.

How tank size changes the answer

A 20-gallon long is the sensible floor — footprint matters more than height for a strong swimmer. One male with two or three females reduces sparring and harassment; a males-only group needs more length and broken sightlines. The bigger the swimming lane, the calmer the group.

Swordtail community ideas

Each build is scored by the same engine as the planner — tap one to load it.

Common questions

More on Swordtail

Related guides on TankStocking — each scored by the same welfare engine as the planner.

Compatibility is a planning estimate: individual temperament, tank layout, and group sizes all matter. Cycle the tank, add fish gradually, and watch how they behave. See the methodology or browse the full freshwater fish list.