Geophagus winemilleri

Overview

Geophagus winemilleri is an eartheater associated with the upper Negro and connected waterways. A dark marking before the gill cover, four downward-slanting flank bars, and a red tail patterned with blue-white spots help identify it. Sales names should be checked against provenance.

Distribution & habitat

Confirmed collections come from southern Venezuela in the upper Negro, Siapa, and Casiquiare waterways. Northern Brazil is a probable extension; a wider Negro distribution and occurrence in the Orinoco drainage remain uncertain.

It may be restricted to acidic, mineral-poor black water. Favored sites have gently sloping sandy or muddy margins, sometimes with stones, submerged roots, branches, and leaves. A waterway connection alone does not establish its presence throughout an adjoining basin.

Aquarium setup

Provide at least about 180 × 60 cm of floor space and soft sand. Coarse gravel obstructs sifting and risks gill injury or internal problems if swallowed. Dim lighting, wood, roots, and flat stones work well. Heavy leaf deposits can produce suspended debris that blocks equipment.

Use a mature aquarium with stable conditions, generous external or sump filtration, and weekly water changes of at least 50–70%. Mechanical media should retain fine particles; protect pumps from continual sand intake. Diffuse returns to avoid strong currents. Poor upkeep may accompany head and lateral-line erosion or impaired growth.

Diet & feeding

The genus obtains food by sifting substrate, with wild diet records including small invertebrates, seeds, and organic debris. Supply fine prepared foods with small live or frozen items and plant-rich formulations. Even adults need modest-sized particles. Three or four small daily feedings suit their browsing behavior.

Behaviour & compatibility

Usually peaceful outside breeding, it can share with calm fish requiring similar water. Avoid aggressive bottom-territory holders and hard-water specialists. A group of five to eight is a useful starting recommendation, with observation of hierarchy and subordinate fish. Eartheaters are not invariably safe alongside freshwater stingrays.

Sexual dimorphism

External differences are unreliable except for the female's ovipositor during spawning.

Breeding

Parents deposit and guard eggs on a surface, then mouthbrood the hatched young. Allow juveniles to form pairs; maturity may take at least a year. The female tends the eggs while the male guards nearby.

Hatching occurs at approximately 72 hours. Usually the female gathers larvae first, although some males participate sooner. Later care may involve shared holding, exchanges of the entire brood, or only one parent. Fry swim freely at around eight to eleven days, leaving for increasingly long feeding excursions and returning when threatened. Powdered foods, brine shrimp nauplii, and microworms are appropriate. Provide protected rearing space in a mixed aquarium.

Notes

The dark flank spot lies within the second bar. Juveniles can carry an additional tail-base bar that fades with maturity, while tail spots sometimes merge into stripes. Río Negro I and stripetail trade labels cannot automatically be treated as confirmed synonyms.