Xiphophorus hellerii
Males carry the namesake extended tail-fin sword that can equal body length. Active surface-loving livebearer, needs a hood or floating plants because they jump. Like all livebearers, prefers hard alkaline water; struggles in soft acidic blackwater set-ups. 3:1 female:male keeps the peace.
Green Swordtail (Xiphophorus hellerii) reaches 10–14 cm (males include sword) as an adult and needs a minimum tank of 100 L. Native to Central America (southern Mexico to Honduras), it lives in the mid to top water column with a peaceful (males spar) temperament. Aim for 22–28 °C, pH 7.0–8.4, and 12–30 dGH hardness. Lifespan is 3–5 years with good care. Keep green swordtail in groups of 4+, no (live in groups) schoolers need numbers to display natural behaviour. Diet: omnivore, Crushed flake, pellets, blanched veg. Likes the occasional live or frozen mosquito larva. Plant-safe: Mostly (may nip). Shrimp-safe: Adults only.
Care at a glance
Males carry the namesake extended tail-fin sword that can equal body length. Active surface-loving livebearer, needs a hood or floating plants because they jump. Like all livebearers, prefers hard alkaline water; struggles in soft acidic blackwater set-ups. 3:1 female:male keeps the peace.
By Mike ElmiraUpdated 1 min read
Part of our complete guide to aquarium fish for the planted tank.
The parameters that decide whether green swordtail fits in your tank.
Mid to Top
No
Small group of 4+
Poeciliidae
Omnivore
Crushed flake, pellets, blanched veg. Likes the occasional live or frozen mosquito larva.
3–5 yrs
Easy
Fast highland streams of Mexico and Honduras
Central America (southern Mexico to Honduras)
Tank-mate safety and the species this one is documented to thrive (or fail) alongside.
Direct answers to the questions search engines and AI assistants surface most often about this species.
Green Swordtail (Xiphophorus hellerii) needs a minimum tank of 100 L. They live in the mid to top water column and should be kept in groups of 4+, so a longer footprint matters more than depth.
Target 22–28 °C, pH 7.0–8.4, and 12–30 dGH hardness. Acclimate slowly when moving them between water sources.
Shrimp safety: Adults only. Plant safety: Mostly (may nip).
Green Swordtail are omnivore. Crushed flake, pellets, blanched veg. Likes the occasional live or frozen mosquito larva.
On Fin & Stem's 1–5 difficulty scale this species rates 1/5. Almost unkillable, a solid first-tank choice. Breeding difficulty: easy.
Typical lifespan in a well-maintained tank is 3–5 years.
A planted tank is a system. Pair this fish with one entry from each other pillar to plan the whole scape.
