All fish / Poeciliidae

Hook Swordtail

Xiphophorus signum

Also known as hooked swordtail, signum swordtail, chajmaic swordtail, xiphophorus signum, 钩剑尾鱼

A slim, olive to yellowish swordtail with a dark zigzag lateral stripe, and males carry a long sword whose tip curves upwards like a hook. It is a wild species kept mainly by livebearer enthusiasts who want to keep rare, unhybridised Xiphophorus lines going.

Care at a glance

Care level

Moderate

Temperament

Semi

Adult size

6 cm

Temperature

22 to 27 °C

pH

7 to 8

Smallest tank

120 litres

Keep as

One male with several females, or a larger group with plenty of cover

Diet

Omnivore: quality flakes, small live and frozen foods such as bloodworm and daphnia, plus algae and vegetable matter

Swims

Middle of the tank

Lifespan

2 to 4 years

Water

Freshwater

Wild range

Guatemala (Río Chajmaic and upper Río Usumacinta basin)

Breeding

A livebearer, with females giving birth to small broods of fry after about four weeks. It breeds less readily than domestic swordtails and broods are small, so dense plants and a separate rearing tank help keep numbers up.

Good to know

Males can be quarrelsome with each other, and the species should never be kept with other swordtails or platies because they hybridise easily. It needs clean, well-oxygenated water with some current, much like its home streams.