Green Swordtail
Xiphophorus hellerii
The Green Swordtail (Xiphophorus hellerii) is a semi-aggressive fish that's easy to keep. Give it a tank of at least 90 litres (24 US gallons), water held at 68-82°F, and a pH of 6.8-8.2. Always keep a group of at least 6 - they feel safest in numbers.
Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.
Natural distribution
Atlantic-slope rivers from Mexico to Honduras.
- Africa
- South America
- Central America & Mexico
Regional colours match the stocking calculator's origin map.
Green Swordtail Tank Setup
A tank of at least 90 litres (24 US gallons) at 68-82°F and pH 6.8-8.2 suits them well. Livebearers breed quickly, so plan for the fry and keep an eye on your male-to-female ratio. Always keep a group of at least 6 of their own kind - kept alone or in pairs they tend to turn shy, nippy, or wash out in colour. They reach about 15 cm as adults, so don't be misled by the small juveniles sold in stores.
What Do Green Swordtails Eat?
They're not fussy eaters - feed a varied diet, rotating good-quality dry, frozen, and gel foods rather than the same thing every day, and match the food size to their mouths.
Green Swordtail Tank Mates
Keep in groups of at least 6. The Green Swordtail is semi-aggressive, which is the first thing to weigh up when you choose tank mates. It's a shoaling fish, so settle a group of 6 or more of its own kind before adding anything else - a stressed, lonely fish is far more likely to nip or hide. Before you buy, run your full stocking list through our stocking calculator. It weighs temperament, adult size, and water needs together, which a single species page can't do on its own.
Are Green Swordtails Good for Beginners?
Often recommended to beginners, but only after the tank is cycled and you can keep a proper school - not three fish in a new setup.
Green Swordtail - frequently asked questions
What size tank do Green Swordtails need?
Green Swordtails need a tank of at least 90 litres (24 US gallons). A bigger tank is always easier to keep stable, and gives them more room to settle in and behave naturally.
How many Green Swordtails should I keep together?
Keep a group of at least 6. Green Swordtails are a shoaling species and become stressed, lose their colour, or hide when kept singly or in pairs.
What water parameters do Green Swordtails need?
Keep them at 68-82°F with a pH of 6.8-8.2, steady rather than chased to an exact figure. In a cycled tank, ammonia and nitrite should both read 0 ppm, with nitrate kept low through regular water changes.
What do Green Swordtails eat?
Green Swordtails are omnivores and aren't fussy eaters. Feed a varied mix of good-quality dry, frozen, and gel foods, and match the food size to their mouths. Feed small amounts once or twice a day, and remove anything they don't eat.
Are Green Swordtails good for beginners?
Yes - Green Swordtails are a good beginner choice once the tank is fully cycled and you can keep a proper group. They are hardy but still need stable water and a school to feel secure.
Common mistakes with Green Swordtails
- Buying fewer than 6 - Green Swordtails need a proper school to feel secure; isolated individuals hide, fail to colour up, or become stressed.
Building a community? Run the full list through the stocking calculator before you add anything else.
Great tank mates
Chosen from temperament, overlapping temperature/pH bands, plausible minimum tank footprints, and size versus yours in App-aquatic data. Hobby nuance always wins - verify stocking and temperament before purchasing.
Fish to avoid mixing with Green Swordtails
These well-known species are commonly sold alongside this fish but are not recommended tank mates - verify before purchasing.
- OscarPredator - Oscar will eat or injure smaller tank mates
- Pea PufferPredator - Pea Puffer will eat or injure smaller tank mates
- Betta (Male)Predator - Betta (Male) will eat or injure smaller tank mates
