Geophagus surinamensis

Geophagus surinamensis is native to the Surinam River and associated drainage systems in Suriname and French Guiana, inhabiting slow to moderately flowing rivers with soft, slightly acidic water and sandy or silty substrates. It is one of the larger members of the Geophagus genus, with adults reaching 25 cm in length.

Adult males are impressive fish displaying a greenish-grey body with horizontal rows of iridescent blue-green scaling, along with distinctive red-orange stripes and spots on the cheeks and operculum. These markings intensify during breeding and display. Females are similar in pattern but less vividly colored.

Like all Geophagus species, G. surinamensis is a specialized substrate sifter, continuously taking mouthfuls of sand and filtering out invertebrates, organic particles, and food items. This behavior is essential for its wellbeing and requires a deep, fine sand substrate in the aquarium. Coarse gravel will prevent this natural behavior and cause stress.

In the aquarium G. surinamensis is peaceful and social, doing best when kept in groups of 5 or more individuals. It is a mouthbrooder; after spawning on the substrate, the female (or both parents depending on the population) collects the eggs in the mouth and incubates them for 10–14 days. This group dynamic and breeding behavior make it a fascinating species to observe in a large, well-managed aquarium.

Tank Setup A minimum 300-liter tank is needed, preferably larger for a group. Provide at least 7–10 cm of fine white or river sand. Use smooth river stones, driftwood, and robust plants like Vallisneria and Anubias for structure without obstructing swimming space. Avoid sharp décor that could injure the fish during sifting. Excellent filtration is essential as continuous substrate sifting suspends fine particles.

Water Parameters Maintain temperature 24–30°C, pH 5.5–7.0, GH 2–10, KH 1–5. Soft, slightly acidic water is strongly preferred. The addition of Indian almond leaves or peat filtration is beneficial. Perform 25–30% weekly water changes. High water quality is important; these fish are sensitive to elevated nitrates.

Feeding Omnivorous eartheater; feed sinking pellets, eartheater granules, frozen bloodworms, daphnia, brine shrimp, and blanched vegetables. Scatter food across the substrate to encourage natural sifting. Avoid feeding exclusively at the surface; food should reach the bottom. Feed once or twice daily.

Tankmates Peaceful; best kept in groups of 5 or more to distribute any intraspecies aggression. Compatible with large peaceful tetras, other Geophagus species, Festivum Cichlids, Flag Cichlids, large peaceful catfish, and similarly sized non-aggressive cichlids. Avoid aggressive species that will intimidate them.

Breeding Mouthbrooding species. The pair spawns on the substrate; the female collects eggs in the mouth and incubates them for 10–14 days. The fry are free-swimming after release and can accept newly hatched brine shrimp immediately. Both parents may retrieve fry into the mouth during perceived threats.