Geophagus sp. Alto Sinu

A Little More Information...

Geophagus sp. Alto Sinú

Geophagus sp. Alto Sinú is a South American cichlid still identified by an aquarium trade name and associated with the Sinú River basin in Colombia. Like other eartheaters, it sifts substrate through its mouth to locate small prey and organic particles. This form remains uncommon in the hobby, making it appealing to aquarists interested in distinct geographic populations. Available fish are wild-collected, so they benefit from careful acclimation, stable water and a layout that reflects a tropical stream with a sandy bottom.

General description

Geophagus sp. Alto Sinu is a benthic cichlid belonging to the eartheater group and is valued for its natural sifting behaviour. It spends much of the day close to the bottom, taking in sand, sorting it in the mouth and expelling the particles through the gill openings. This feeding behaviour requires a fine, rounded and non-abrasive substrate. Juveniles are usually more silvery and less colourful, while adults develop a heavier body and stronger contrast. It is generally sociable when young, but adults establish a hierarchy and may defend small areas, especially during breeding.

Geographic origin and biotope

Country: Colombia. The name Alto Sinú refers to the upper section of the Sinú River basin in northwestern Colombia. The biotope is associated with warm tropical freshwater, usually over sand, silt and small amounts of plant debris. Banks may include roots, submerged branches and dense riparian vegetation, while aquatic plants may be limited in the main channel. In an aquarium, effective filtration, good oxygenation and regular water changes are important for providing clean, stable water.

Precise locality and local name

The available geographic designation is Alto Sinú, within the Sinú River basin of Colombia. The fish is mainly known in the aquarium trade as Geophagus sp. Alto Sinu, rather than by a clearly established Colombian vernacular name. The term “eartheater” is commonly used for Geophagus in English because of its habit of filtering substrate. To preserve the geographic identity of this form, it is best to retain the Alto Sinú designation and avoid mixing it with other Geophagus populations.

Appearance and physical characteristics

This form has an oval, laterally compressed body, a relatively broad head and a protrusible mouth adapted for sifting sand. The base colour is often silvery to beige, with bluish or greenish iridescence, a dark flank marking and fins that may show red, orange or blue tones depending on age and mood. The dorsal and anal fins may extend into points in adults. Colour usually becomes stronger in good water quality, in dominant fish and during reproductive behaviour.

General diet

Geophagus sp. Alto Sinu is an omnivore with a detritivorous tendency, searching the substrate for small invertebrates, larvae, tiny crustaceans, algae and organic matter. In aquariums, provide a varied diet of quality sinking pellets, frozen foods and occasional suitable live foods. Feed small portions so every fish can eat without overloading the bottom. Very fatty foods or an exclusively meaty diet should be avoided; variety and digestibility are more important than a high proportion of animal protein.

Essential data

• River of origin: Sinú River
• Local name used: Alto Sinú; Alto Sinú eartheater in the aquarium trade
• Origin of the scientific name: Geophagus is the genus name; sp. indicates an undesignated species
• Etymology of the full name: Geophagus means “earth-eater”; Alto Sinú refers to the upper part of the Sinú River basin
• Common/vernacular names: Alto Sinú eartheater; Sinú eartheater
• Family: Cichlidae
• Subfamily: Cichlinae
• Name pronunciation: jee-oh-FAH-gus - AL-toh see-NOO
• Discovery: Aquarium form known under the designation Geophagus sp. Alto Sinú
• Maximum adult size: Approximately 20 cm
• Water temperature and pH: 24 to 28 °C; pH 6.0 to 7.5
• Stream appearance and surrounding vegetation: Tropical stream with a sandy or silty bottom, roots, branches and riparian vegetation
• Typical tankmates: Geophagus pellegrini, Geophagus steindachneri, Andinoacara pulcher, Hoplisoma metae
• Temperament and behaviour: Generally peaceful, social and active near the bottom; hierarchy and territorial behaviour increase during breeding
• Water depth: Shallow to medium-depth areas of streams and calmer sections
• Sexual dimorphism: Limited in juveniles; adult males are often larger and more elongated, with more developed fins
• Bottom structure and flow: Fine sand, silt, soft gravel and plant debris; low to moderate flow depending on the section

In your aquarium

For success with wild specimens, use a spacious aquarium, keep an appropriate starting group and provide very fine sand so they can sift without injury. Maintain warm, well-oxygenated water with low waste levels and regular water changes. Roots, open areas and moderate lighting will help them feel secure. Avoid overly aggressive tankmates or fish small enough to be swallowed. Gradual acclimation and a varied diet are the keys to stabilizing these uncommon fish.