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Swordtail tank mates

Swordtail compatibility is mostly a question about male swordtails. Females are straightforward hard-water livebearers that mix like platies. Males run a constant low-level dominance contest, and in a cramped tank that pressure spills onto anything with a long fin or a similar body shape. So the plan is less about which species and more about geometry: one male per tank unless you have 120 cm of length, more females than males, and a lid, because a startled swordtail leaves the water. Tank mates that work share the hard alkaline chemistry and stay out of the argument: platies and mollies as stablemates, corydoras on the bottom, and a calm barb like the cherry barb in the midwater. Avoid anything that nips (a sword-tailed male is a walking target) and anything big enough to see a swordtail as food.

Common mistakeHousing two swordtail males in the same short tank is the dominance mistake that looks like random aggression. Males establish rank fast, and the weaker fish hides until it stops eating. Keep one male, or give a long footprint with heavy planting if you insist on several. Removing plants to make the tank look open usually makes the chasing worse.

Evidence: verified
Confidence: high

Each name below opens a pair check with Swordtail. That check is the decision, not the list itself.

← Full Swordtail profile·Compatibility checker·Tank builder·More livebearer

Usually safer companions

Conservative shortlist from this profile. Open a pair page before you buy.

None listed here. Use the pair checker with species you are considering.

Risky or situational

May work with more water, a mature system, or a species-only setup. Read the pair page before you experiment.

  • BettaOpen pair check

    Both species defend territory. The pairing needs a long footprint and rockwork or planting that breaks the sightline between two defended spots. Betta is rated semi-aggressive, so expect chasing, fin damage, or display behaviour directed at Swordtail. Run the pair checker before stocking.

  • Cherry BarbOpen pair check

    Marked risky or situational on the profile. Tank length and group size change the outcome more than a temperament label does.

  • GuppyOpen pair check

    Marked risky or situational on the profile. Tank length and group size change the outcome more than a temperament label does.

Fish to avoid with Swordtail

Predation, aggression, or space rules on this profile. Treat these as poor default mixes.

  • OscarSee why (pair)

    Oscar reaches 35cm and is flagged predatory. Swordtail at 12cm is prey-sized for it. Oscar needs at least 300L, far above the 80L minimum for Swordtail. The tank that houses one stresses the other.

Tank size and groups

  • Published minimum for Swordtail: 80L. Group minimum 3 .
  • Compatibility changes when the tank is too short for turning, too little for a real school, or too warm for one species and not the other. That is why pair checks include tank context, not only temperament.
  • Nearest litre hub to this minimum: 80L hub.

Easier alternatives to consider

Hardier first-tank names from the library. Still read the profile. Not a substitute for reading this one.

Plan before you buy

Start a pair check with Swordtail, or open a starter plan with the top safer companions in the builder.

Open pair checkerOpen this plan in builder

Tank hubs: 80L

Related reading

Guides that list other fish with the same trait, so you can plan around the group rather than one row.

Filtration & heating

A 80L minimum tank for Swordtail needs a filter rated for at least 320L/hr turnover and a heater maintaining 20–28°C.

Filter size guide →Heater size guide →Tank setup checklist →Beginner plants guide →

Similar fish (same category)

Related (care + temperament)

Other species that list Swordtail

Reverse lookup: these profiles reference Swordtail under safe or “best with” lists.

Featured compatibility checks

Curated pair pages for Swordtail. Each opens a full verdict — not just a list label.

Swordtail tank mates — quick answers

What fish can live with Swordtail?
This hub has no “usually safer” (GOOD) companions for Swordtail. Workable neighbours sit in caution — for example Betta, Cherry Barb, Guppy. Treat every name as a pair check, not a shopping list. Swordtail compatibility is mostly a question about male swordtails.
What tank mates should you avoid with Swordtail?
Avoid Oscar based on size, temperament, or predation risk on this profile.
What size tank do Swordtail need for a community?
100L is the practical floor and 90 cm length gives a real run. Keep a tight lid; swordtails jump.