Swordtail
Xiphophorus hellerii
beginner careOverview
The swordtail (Xiphophorus hellerii) is a large, energetic livebearer named for the long sword-like extension on the male’s tail. Available in reds, greens, blacks and pineapple patterns, it is hardy and beginner-friendly but noticeably bigger and more active than a platy or guppy — so it needs real swimming room. Peaceful overall, males can be a little pushy with each other, which shapes how you stock them.
Tank & water
Swordtails are powerful swimmers that grow larger than they look in the shop. Give a group at least 75 litres (20 gallons) in a long tank.
- Temperature: 22–28 °C, held with a heater.
- Water: hard and neutral to alkaline, pH 7.0–8.2; most tap water suits them.
- Filtration: a good filter handles their bioload; they enjoy some current.
- A lid: essential — swordtails jump readily, especially the males.
Feeding
Swordtails are hearty omnivores with an appetite for vegetable matter. A quality flake or pellet with good plant content is the staple, alongside blanched vegetables, algae-based foods and frozen or live protein such as bloodworm, daphnia and brine shrimp. Vegetable matter is important for their digestion, so don’t rely on protein alone. Feed small amounts once or twice a day and avoid overfeeding these greedy eaters, as leftover food quickly fouls the water in a tank this heavily stocked.
Tankmates
Peaceful with other species, swordtails suit an active hard-water community: platies, mollies, larger tetras, rainbowfish, corydoras and peaceful catfish. Their size means very small nano fish may be intimidated, so pair them with similarly robust tankmates. Avoid aggressive or fin-nipping species.
Big, bold and colourful, the swordtail is a rewarding livebearer for anyone with a roomy, cycled tank — see our beginner aquarium picks to house one.
Swordtail — frequently asked questions
How big do swordtails get?
Bigger than most people expect. The body reaches 8–10 cm and males add a long tail extension, so total length can be 12–14 cm. They are strong, active swimmers, which is why they need at least 75 litres and a long tank.
Do male swordtails fight?
Males can be territorial and will chase and spar with each other, especially in a crowded tank. Keep either a single male with several females, or a larger group in a spacious tank so aggression is spread out rather than focused on one fish.
Are swordtails jumpers?
Yes — swordtails are notorious jumpers, particularly startled males. Always keep the tank covered with a lid to prevent losses.
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