Trout Goodeid

The Trout Goodeid, scientifically known as Ilyodon furcidens, is a robust livebearing fish native to fast-flowing rivers and streams in west-central Mexico, particularly in the states of Jalisco and Michoacán. It is named for its speckled, trout-like patterning and is valued in the hobby for its hardiness, active behavior, and ecological significance as a threatened species in the wild.

Adult Trout Goodeids typically reach about 3 to 4 inches (7.5 to 10 cm) in length. Males are slightly smaller and often exhibit more vivid coloration, with bluish, green, or gold iridescence along the flanks and darker spotting. Females are rounder and more subdued in color. Both sexes display a distinctive caudal peduncle and tail that resemble the markings of a juvenile trout.

A tank of at least 30 gallons is recommended for a group. Trout Goodeids are active swimmers and thrive in aquariums with a strong current, rocky substrate, and plenty of oxygenation. Decorate with smooth stones, driftwood, and hardy plants that can tolerate flow, such as Java fern or Anubias. A secure lid is essential, as they are capable jumpers.

Water parameters for Ilyodon furcidens should include a temperature range of 68 to 75°F (20 to 24°C), a pH between 7.0 and 8.0, and moderately hard to hard water. They tolerate cooler water well, making them suitable for unheated tanks in temperate climates. Clean, well-filtered water and regular maintenance are important for long-term health.

Feeding Ilyodon furcidens is simple, as they are omnivorous with a strong herbivorous tendency. Offer a staple diet of high-quality spirulina flakes or algae-based pellets, supplemented with blanched vegetables such as spinach or zucchini. Occasional protein in the form of live or frozen foods like daphnia or bloodworms can be included but should not dominate the diet.

Trout Goodeids are generally peaceful but active and somewhat pushy, especially during feeding. They do best in groups and can be kept with other livebearers or similar-sized, non-aggressive species. Avoid slow-moving or timid fish that may be stressed by their energetic behavior.

Breeding Ilyodon furcidens is straightforward. They are livebearers, but unlike most Poeciliids, Goodeids have a different reproductive method involving a trophotaenia—a specialized structure used by fry to absorb nutrients in the womb. Gestation lasts around 6 to 8 weeks, and fry are relatively large at birth. Adults may eat young if not well-fed or if hiding spaces are lacking.

Ilyodon furcidens (Trout Goodeid) is a fascinating, lively species ideal for aquarists seeking a cooler-water community or river-style biotope with an active, conservation-minded edge.