Pearl Cichlid
Geophagus brasiliensis
South America's 'earth eater': takes mouthfuls of sand, filters them through the gills extracting micro-organisms, and spits out the residue. This 'earth eating' behavior is unique and hypnotic to watch. Olive-green body with pearly iridescent scales and a central black spot. Tolerant of low temperatures (down to 14 °C). Reaches 25+ cm — large tank mandatory.
Water Temperature
20 - 28 °C
pH Value
6 - 8
Water type
Freshwater
Tank level
Bottom and middle
Adult size
25 cm
Minimum tank volume
>= 200 L
Minimum group
>= 2
GH
4 - 15 dGH
KH
2 - 7 dKH
TDS
80 - 295 ppm
Conductivity
125 - 461 uS/cm
Species description
Geographical Origin and Habitat: Extremely widespread throughout southern Brazil and Uruguay. It is not a true Amazonian fish: it inhabits coastal rivers, lakes and even brackish lagoons with muddy bottoms and distinctly cooler temperatures compared to the Amazon basin.
Taxonomy and Morphology: Pearl Cichlid. Belongs to the "brasiliensis" complex (often not true Geophagus). Much stockier and more aggressive build compared to classic eartheaters; easily reaches 25-28 cm (10-11 inches) in length and considerable thickness.
Social Behavior: Unlike true Geophagus (peaceful and gregarious), the brasiliensis is an extremely territorial, irascible and solitary fish (or to be kept in a single pair). Closely resembles the brawling character of large Central American Cichlids.
Coloration and Sexual Dimorphism: Background varying from dark olive green to gray, literally studded with hundreds of huge light blue, golden and white "pearls". A large black ocellus stands out in the center of the flank. Adult males develop a colossal and evident nuchal hump and pointed fins.
Care, breeding and tankmates
Aquarium Setup: Robust tank of at least 300 liters (80 gallons) for a pair. Despite the name, they dig the sand much less, preferring to move large pebbles to delimit their territory. Spartan furnishings with heavy stones glued to the bottom, large woods. They destroy delicate plants.
Diet and Feeding: Extremely voracious omnivore (not a filter-feeding micro-predator). Greedily accepts huge cichlid pellets, whole earthworms, shelled shrimp, mussels and strips of fish. Supplement weekly with peas and spirulina for intestinal health.
Water Quality: A stainless rock. Perfect fish for beginners of large cichlids thanks to its frightening tolerance: pH 6.0-8.0, GH 4-15, temperatures even very cool (20-28°C / 68-82°F). Also tolerates and thrives in slightly brackish waters.
Compatibility and Cohabitation: In small tanks it will kill its own kind and other fish. Cohabits well only in giant tanks (over 600 liters / 150 gallons) with other giants with a strong temperament: Jack Dempsey, Oscars, large armored Loricariids. Absolutely unsuitable for peaceful fish or true Geophagus.
Aquarium Breeding: Open substrate spawners (not mouthbrooders). The pair obsessively cleans a flat stone or the bottom glass, laying up to 800 eggs. The violence with which they defend the offspring is unprecedented: they will ruthlessly attack the breeder's siphon.
Risks and Diseases: Very robust from a pathological point of view. The most serious risk in the aquarium hobby is mistaken identity: sold as a peaceful eartheater, it ends up decimating tankmates. Subject to Hexamita (holes in the head) only if kept in filthy water.
Geographic Origin and Distribution
Extremely widespread throughout southern Brazil and Uruguay. It is not a true Amazonian fish: it inhabits coastal rivers, lakes and even brackish lagoons with muddy bottoms and distinctly cooler temperatures compared to the Amazon basin.
Origin
Cosmopolitan or introducedAmazon, Orinoco, and Guianas
Fish profile
- Temperament
- Semi-aggressive
- It is a mild-mannered cichlid. Unprovoked aggression is very rare. It is a wonderful centerpiece fish.
- Diet
- Omnivore
- It is an eartheater. Feed sinking pellets and frozen bloodworms. A fine sand substrate is mandatory.
- Life expectancy
- 8-15 years
- This robust cichlid can live between 8 and 15 years if housed in a well-managed aquarium and fed a varied diet. Good water maintenance and the absence of sudden temperature fluctuations contribute significantly to its longevity. With age, males develop a characteristic nuchal hump that makes them look even more impressive.
- Adult size
- 25 cm
- The catalog's scalar value is 25 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 28 cm for this species, recorded as total length (TL). The taxonomic record consulted is Geophagus brasiliensis (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Group
- Keep them in groups. This diffuses natural aggression. Pairs will emerge as they mature.
- Feeding frequency
- Twice daily
- It constantly sifts the sand. Feed multiple small meals daily. This mimics natural continuous foraging.
- Bioload
- High
- This fish produces a high bioload. Robust biological filtration is essential. Frequent water changes are necessary.
- Flow
- Strong
- It originates from riverine environments. It prefers moderate water flow. Provide resting areas with calm water.
- Jump risk
- No
- Reproduction
- Mouthbrooder
- Many are mouthbrooders. Parents fiercely guard eggs and fry. Breeding pairs form naturally over time.
- Compatibility & tankmates
- Aggressive
- It is generally peaceful. It fits well in community tanks. It becomes territorial during spawning.
- Tank level
- Middle/Bottom
- It stays at the bottom. It continuously sifts the sand. A large footprint is required.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 2.6 ± 0.26 se
- Resilience
- Medium (1.4 - 4.4 years)
- Phylogenetic uniqueness (PD50)
- 0.5
- Bayesian Length-Weight
- a = 0.01905, b = 3.02
- VulnerabilityLow vulnerability (18 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
Related species
Recommendations grouped by close relatives, companion choices, and similar care.
