All fish / Goodeidae

Redtail Splitfin

Xenotoca eiseni

Also known as redtail goodeid, red tail splitfin, red-tailed goodeid, xenotoca, orange tail goodeid, eiseni, ゼノトカ・アイセニ, 红尾古德鱼

Males are deep-bodied with a bright humped back that shows a bluish sheen, and a vivid orange to red tail end. Females look plainer and greyish. It is a hardy livebearer that copes with cooler, hard water, and many keepers want it because it is rare and threatened in the wild.

Care at a glance

Care level

Easy

Temperament

Semi

Adult size

6 cm

Temperature

18 to 26 °C

pH

7 to 8.2

Smallest tank

100 litres

Keep as

Group of 6 or more, with more females than males

Diet

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

Swims

Middle of the tank

Lifespan

3 to 5 years

Water

Freshwater

Wild range

Mexico: Pacific slope drainages of Nayarit and Jalisco, including the upper Río Grande de Santiago area

Breeding

It is a livebearer. Females carry young that are fed through a trophotaenia, a cord-like structure similar to a placenta, and give birth to about 10 to 40 large, well-developed fry after roughly 8 weeks. Breeding in captivity is easy, and the fry can take crushed flake or baby brine shrimp straight away.

Good to know

It can nip fins and harass slow or long-finned tankmates, so keep it with robust fish. Wild populations are endangered and have mostly disappeared, so keep separate lines that are not crossed with other populations.