Retroculus Xinguensis

Datasheet

General Description

Retroculus xinguensis, a member of the Cichlidae family and order Perciformes, is a species that can be identified by specific morphological characteristics such as the number of dorsal and anal fin rays, scale count, and gill raker presence. It is considered a peaceful fish outside of breeding periods, preferring to coexist with pelagic species rather than benthic ones. Sociable in nature, these fish tend to form loose groups, with juveniles showing a strong tendency to group together.

Aquarium Setup

For the optimal care of Retroculus xinguensis, it is recommended to maintain them in an environment that mimics a flowing river. The tank should have soft sand mixed with small pebbles, along with rocks, boulders, roots, branches, and hardy aquatic plants. To thrive, these fish require pristine water conditions with high oxygen levels and water movement. Regular water changes of 30-70% weekly are essential, and the use of additional equipment like powerheads and pumps may be necessary. These fish may require a prolonged quarantine period due to their sensitivity post-import.

Behaviour

Retoculus xinguensis typically displays peaceful behavior, except during breeding periods when they may become territorial and aggressive towards smaller tankmates. It is recommended to keep them in groups of 5-8 individuals to establish a natural dominance hierarchy and prevent excessive antagonism. Weak specimens may be targeted by dominant individuals if kept in smaller numbers, causing the group to behave nervously.

Feeding and Diet

In their natural habitat, Retroculus xinguensis primarily feeds on benthic aquatic invertebrates such as chironomid larvae, trichoptera, and ephemeroptera larvae. In an aquarium setting, they should be offered a varied diet consisting of high-quality prepared foods, live or frozen larvae, small fish, and vegetable-based products. Feeding them 3-5 small meals a day is recommended for optimal growth and health.

Reproduction & Dimorphism

These fish are biparental substrate-spawners, with courtship initiated by the male before the female deposits eggs in excavated pits. The eggs are adhesive and cared for by both parents until hatching, after which the fry are guarded and fed. Adult males exhibit more slender bodies than females, with pronounced differences in the shape of the ventral and anal fins. Mature males also develop increased red pigmentation in their fins during the breeding season.

Habitat and Distribution

Retoculus xinguensis is a rheophilic species typically found in fast-flowing, clear-water rivers with boulders and sandy or gravel substrates. Its distribution is primarily in the lower rio Xingu basin in northern Brazil, including tributaries such as the rio Iriri. Other records exist from rivers like the rio Jamanxim and rio Arapiuns. The species' range extends to Mato Grosso state and various other tributaries in the Amazon main channel.