All fish / Poeciliidae

Sheepshead Swordtail

Xiphophorus birchmanni

Also known as sheepshead swordtail, birchmann's swordtail, birchmanni, x. birchmanni, sheep head swordtail, バーチマニー, 羊头剑尾鱼

A stocky wild swordtail without a sword, whose adult males grow a humped head and a tall, sail-like dorsal fin with dark vertical bars along a silvery-olive body. Hobbyists keep it as an unusual natural species, and it is well known in research for hybridising with Xiphophorus malinche in the wild.

Care at a glance

Care level

Moderate

Temperament

Semi

Adult size

6 cm

Temperature

20 to 26 °C

pH

7 to 8

Smallest tank

100 litres

Keep as

Group with more females than males, e.g. 1 male to 2 or 3 females

Diet

Omnivore: quality flakes and granules, algae and vegetable matter, plus live or frozen bloodworm, daphnia and brine shrimp

Swims

Middle of the tank

Lifespan

3 to 5 years

Water

Freshwater

Wild range

Mexico: Río Pánuco basin (Río Tempoal, Río Moctezuma, Río San Pedro tributaries)

Breeding

A livebearer: females give birth to batches of 20 to 40 fry about every four weeks after internal fertilisation. It breeds readily in a well planted tank, and adults may eat the fry unless dense cover or a separate rearing tank is provided.

Good to know

Males can be quarrelsome with each other, so give plenty of space and cover, and do not keep it with other swordtails or platies because it hybridises easily. It likes clean, well-oxygenated water with some current.