1 kinds · tap one for a closer look
Active and somewhat pushy; males chase each other and may nip fins.
406 species in our list are a good match.
Active and somewhat pushy; males chase each other and may nip fins. Keep one male to several females in a roomy tank.
Algae, spirulina flakes, frozen foods and some vegetable matter; a good algae grazer.
Tap a food to see what it is.
Males are far more colourful, with an orange-red caudal peduncle and tail and a blue rear body, develop a higher back with age, and have a notched anal fin (andropodium). Females are plain brownish-grey with a gravid spot.
Common problems. Tap one to see the signs. This is a guide, not a diagnosis.
Livebearer · Moderate
Easy livebearer; young are nourished in the womb through trophotaeniae. Females do not store sperm, so they must mate for every brood. Gestation 7-8 weeks; the large fry eat adult foods at once and parents rarely eat them.
One male with 4-5 females.
Planted 100 L tank, hard alkaline water and plenty of cover.
Cool-ish water and a well-fed group.
5-50 large fry per brood after 7-8 weeks.
Newborns are large and take baby brine shrimp or crushed flake at once.
A goodeid from western Mexico whose young are fed in the womb through trophotaeniae, structures that work like a placenta. Males have orange-red tails and can be aggressive fin-nippers.
Cloudsley Rutter described this goodeid in 1896. Its humped back and orange-red tail have made it one of the most popular splitfins in aquariums.
First described by Cloudsley Rutter in 1896. Named for Named after naturalist Gustav Eisen.
14 facts checked with sources
Valid as Xenotoca eiseni (Rutter, 1896) per Catalog of Fishes, but some recent works (Huber 2019, Page et al. 2023, Fricke et al. 2024) use Xenoophorus eiseni, and the GWG writes "Xenotoca" eiseni pending a new genus. In 2016 the species was split into X. eiseni, X. doadrioi and X. lyonsi; many aquarium 'redtail splitfins' are actually X. doadrioi (males with a golden band/saddle, per GWG) or X. lyonsi. Ask for the collection locality.
Eschmeyer's Catalog of Fishes (species, genus Xenotoca) · Goodeid Working Group: Xenotoca eiseniLegacy has no family field.
FishBase: Xenotoca eiseni summarysize-pick: Seriously Fish 6.0 cm SL (about 7 cm TL with tail); FishBase 7 cm TL for females, 6 cm TL males. The GWG/Miller et al. (2005) 7.5 cm SL is a single wild maximum record and is kept in the note only.
Seriously Fish: Xenotoca eiseni · FishBase: Xenotoca eiseni summary · Goodeid Working Group: Xenotoca eiseniLegacy 20-26 lies within Seriously Fish 15-30. GWG advises not keeping it constantly above 25 °C and giving a winter rest below 20 °C for 2-3 months.
Seriously Fish: Xenotoca eiseni · FishBase: Xenotoca eiseni summary · Goodeid Working Group: Xenotoca eiseniBoth sources 6.0-8.0; legacy 7-8.5.
Seriously Fish: Xenotoca eiseni · FishBase: Xenotoca eiseni summaryLegacy has no hardness; Seriously Fish range recorded.
Seriously Fish: Xenotoca eiseni · FishBase: Xenotoca eiseni summarySeriously Fish: 60 x 30 cm base x 30 cm = 54 L. The Goodeid Working Group recommends far more (250 L) for a breeding colony. Legacy 100 L sits between.
Seriously Fish: Xenotoca eiseni · Goodeid Working Group: Xenotoca eiseniLegacy 's' = semi-aggressive. Seriously Fish warns it is particularly hostile to catfish (e.g. Corydoras) and recommends a species tank.
Seriously Fish: Xenotoca eiseniSeriously Fish rates it Easy and very hardy; legacy 2 (moderate). The difficulty is tankmate choice, not care.
Seriously Fish: Xenotoca eiseniLegacy has no range field. IUCN: Endangered (assessed 14 March 2018, per FishBase). The Tepic population is probably extinct (GWG).
Eschmeyer's Catalog of Fishes (species, genus Xenotoca) · Goodeid Working Group: Xenotoca eiseniMatches legacy in substance. Legacy 'olive-silver' females: GWG says brown/brownish grey.
Seriously Fish: Xenotoca eiseni · Goodeid Working Group: Xenotoca eiseniGWG says fry are often eaten in their experience; Seriously Fish says rarely.
Seriously Fish: Xenotoca eiseniLegacy 10-30 fry after 8 weeks: the range is narrower than Seriously Fish 5-50.
Seriously Fish: Xenotoca eiseni · FishBase: Xenotoca eiseni summaryLegacy text is right in substance; 'placenta-like trophotaeniae' is accurate. Quote 2 is from the profile summary.
Seriously Fish: Xenotoca eiseni