Green Swordtail

Xiphophorus hellerii

Freshwater Central America Usually captive bred

A livebearer where males grow a long tail spike. Males squabble over females, so keep one male to several females. It jumps readily, so a lid is a must. Breeds easily and can overrun a small tank.

12 cm adult length, drawn to scale. slim body.

Try it in the planner Opens a tank sized to its minimum with 1 fish added.

What it needs

Item	Value	Because
Adult length	12 cm	Used for the Space check: the tank must be long enough for the fish to turn round.
Smallest tank	90 L, at least 80 cm long estimated	The least water and floor length this species is kept in for good, as a single fish or smallest group.
Extra water per added fish	8 L estimated	What each further fish adds once the minimum is met.
Waste load	Class 2 of 5 estimated	How much waste an adult makes against its size. Feeds the Load check.
Temperature	21 to 27 C	Stock sharing a tank need overlapping ranges.
pH	7 to 8.3	Compared with tankmates in the Water check.
Hardness	GH 10 to 25, KH 6 to 16	Degrees of general and carbonate hardness.
Flow	Medium	Low-flow fish are stressed in a strong current.
Light	Moderate	Matched to the lighting class on the needs sheet.
Group size	Single fish is fine	Not a schooling species.
Temperament	Peaceful	Territorial: weak.
Swims in	Middle water	Fish that use different levels share a tank more easily.
Lifespan	About 4 years	A fish is a long commitment.
Experience	Suits a first tank	A guide to how forgiving the species is of mistakes.
Jumps	Yes	Keep the tank covered.

Tags marked estimated are judged from the size and habits of the species rather than measured, so treat them as a sensible default.

Diet and tank layout

Green Swordtail is an omnivore that swims in the middle of the tank. It is safe with plants. Give it some cover.

Tankmates

Works with

Depends

Avoid

Compare any two fish on the compatibility page, or print the equipment for a stock on the needs sheet. How this is worked out: the method.