Geophagus

Also known as: Geophagus surinamensis

Geophagus surinamensis, commonly known as the Surinam eartheater, is a medium-sized cichlid distinguished by its elongated body, subtle iridescent scales, and specialized mouth adapted for sifting sand. The Geophagus originates from Amazon River basin in Suriname, Guyana, and French Guiana, inhabiting slow-moving, sandy-bottomed rivers and floodplain lakes with submerged vegetation and leaf litter., reaches Adult size: 15-20 cm in captivity, typically lives 8-12 years in captivity with proper care; wild specimens may live shorter due to predation and environmental factors., and is kept at 24-28°C (75-82°F); stable temperatures within this range are critical for metabolism and immune function.. Individual fish vary, so treat this as a general guide rather than a guarantee.

Species at a glance

Origin: Amazon River basin in Suriname, Guyana, and French Guiana, inhabiting slow-moving, sandy-bottomed rivers and floodplain lakes with submerged vegetation and leaf litter.
Adult size: Adult size: 15-20 cm (6-8 inches) total length; males typically larger than females, reaching up to 20 cm in optimal conditions.
Life span: 8-12 years in captivity with proper care; wild specimens may live shorter due to predation and environmental factors.
Temperament: Generally peaceful and social, best kept in groups of 5+; exhibits mild territoriality during breeding but rarely aggressive toward tankmates of similar size.
Tank size: Minimum 200 liters (53 gallons) for a group of 5-6 individuals; 250+ liters (66+ gallons) recommended for long-term stability and natural behavior expression.
Water temp: 24-28°C (75-82°F); stable temperatures within this range are critical for metabolism and immune function.
pH range: pH 5.5-7.0; prefers soft, slightly acidic to neutral water mimicking blackwater tributaries of the Amazon.
Diet: Omnivorous detritivore; feeds on organic matter, microorganisms, and small invertebrates sifted from substrate in nature; in captivity, accept high-quality sinking pellets, frozen bloodworms, brine shrimp, and blanched vegetables like zucchini or spinach.
Other names: Geophagus surinamensis

About the Geophagus

Geophagus surinamensis, commonly known as the Surinam eartheater, is a medium-sized cichlid distinguished by its elongated body, subtle iridescent scales, and specialized mouth adapted for sifting sand. It exhibits a natural behavior of continuously taking mouthfuls of substrate, filtering out edible particles, and expelling debris through the gills—a trait that aids in tank substrate maintenance. This species is highly social and thrives in groups, displaying complex interactions and subtle color shifts during social encounters. In the wild, it inhabits tannin-stained waters with dense leaf litter, relying on its foraging strategy to exploit nutrient-rich detritus.

Lifespan and health

With optimal care, Geophagus surinamensis commonly reaches 10-12 years, and exceptional individuals have been documented living up to 15 years in well-maintained, species-specific setups. Lifespan is strongly correlated with water quality, diet diversity, and low stress levels; chronic exposure to suboptimal pH (>7.5), high nitrates (>40 ppm), or inadequate substrate depth significantly reduces longevity by increasing susceptibility to disease and metabolic strain. Regular health monitoring—observing feeding response, sifting behavior, and fin condition—is essential; lethargy, loss of appetite, or clamped fins often precede illness by 24-48 hours. Common health issues include intestinal parasites (e.g., Capillaria) from live food, manifesting as weight loss despite normal appetite, treatable with fenbendazole-based medications; bacterial infections like fin rot or ulceration, often secondary to poor water quality, requiring improved parameters and topical antibiotics such as methylene blue or erythromycin; and hole-in-the-head disease (HLLE), linked to vitamin deficiencies and activated carbon overuse, preventable by diversifying diet with vitamin-rich foods and limiting carbon use to <4 weeks at a time. Quarantine new fish for 4-6 weeks and avoid overcrowding to minimize pathogen spread.

Overview

Geophagus surinamensis, commonly known as the Surinam eartheater, is a medium-sized cichlid distinguished by its elongated body, subtle iridescent scales, and specialized mouth adapted for sifting sand. It exhibits a natural behavior of continuously taking mouthfuls of substrate, filtering out edible particles, and expelling debris through the gills—a trait that aids in tank substrate maintenance. This species is highly social and thrives in groups, displaying complex interactions and subtle color shifts during social encounters. In the wild, it inhabits tannin-stained waters with dense leaf litter, relying on its foraging strategy to exploit nutrient-rich detritus.

Care and tank setup

Tank setup should prioritize a fine, smooth sand substrate (0.5-2 mm grain size) at least 5-7 cm deep to allow natural sifting behavior; avoid gravel or sharp materials that can damage gills. Provide driftwood, leaf litter (e.g., Indian almond leaves), and sparse rocky caves for shelter, but keep open swimming areas central. Filtration must be strong yet gentle—turnover rate of 4-5x tank volume per hour using a canister or sponge filter—to maintain pristine water without strong currents that disrupt feeding. Water parameters require strict stability: perform 25-30% weekly water changes, monitor ammonia and nitrite at 0 ppm, nitrate below 20 ppm, and use RO water remineralized to achieve softness (GH 3-6 dGH, KH 1-3 dKH). Temperature should be held constant within 24-28°C using a reliable heater with thermostat; sudden fluctuations >1°C can trigger stress. Feeding should occur 2-3 times daily with small portions of sinking foods; offer a varied diet including 60% protein (frozen bloodworms, daphnia, brine shrimp) and 40% plant matter (spirulina flakes, blanched peas) to prevent nutritional deficiencies. Avoid overfeeding, as excess food decomposes rapidly in sand and degrades water quality. Tankmates must be peaceful, similarly sized (8-15 cm), and non-aggressive; ideal companions include Corydoras catfish, small tetras (e.g., Ember or Neon tetras), peaceful Loricariids like Otocinclus, and dwarf cichlids such as Apistogramma species. Avoid fin-nippers, large predators, or overly active species that may outcompete them for food or disturb their feeding rhythm. Never house with aggressive cichlids like Oscars or Jack Dempseys, as they will stress or injure the Geophagus.

Adding a Geophagus? Research the species’ adult size and temperament carefully, quarantine new fish before introducing them to your tank, and buy from reputable aquarium stores or breeders.

Breed information on this page is based on the Wikipedia article on the Geophagus, supplemented with additional research. Reviewed for accuracy.