All fish / Poeciliidae

Monterrey platyfish

Xiphophorus couchianus

Also known as monterrey platy, northern platyfish, couch's platyfish, couchianus platy, 蒙特雷剑尾鱼

A small, stocky wild platyfish with an olive to silvery body, faint dark markings and, in males, yellowish fins. It has none of the bright colours of domestic platies. Hobbyists keep it mainly to help conserve a species that is almost gone from the wild and to keep genetically pure lines going.

Care at a glance

Care level

Moderate

Temperament

Peaceful

Adult size

4.5 cm

Temperature

20 to 26 °C

pH

7 to 8

Smallest tank

60 litres

Keep as

Group of 6 or more, with more females than males

Diet

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

Swims

Middle of the tank

Lifespan

2 to 4 years

Water

Freshwater

Wild range

Mexico: upper Río San Juan basin (Río Santa Catarina) around Monterrey, Nuevo León

Breeding

Like other livebearers it gives birth to live young after internal fertilisation, with broods usually small, often 10 to 30 fry. It breeds readily in a planted tank, though dense cover or a separate rearing tank will improve fry survival.

Good to know

Listed as critically endangered and possibly extinct in the wild, so keep it apart from other Xiphophorus to avoid hybrids and only buy stock with known collection locality. Do not release it and do not mix it up with ordinary domestic platies.