Stone Eartheater
Retroculus lapidifer
The colossal and unattainable 'Stone Eartheater' or 'Rapids Eartheater' (15-20 cm). One of the most clamorous anomalies of the cichlid family, it evolved for life on the rocky bottom of the most violent rapids in South America. It lacks a functional swim bladder, spending its entire life crawling on the bottom or clinging to stones with enormous ventral fins. It demands frightening currents, very high oxygenation and hot waters. Expensive, hyper-active and highly territorial cichlid, it is the undisputed king of extreme River-Tanks.
Water Temperature
26 - 30 °C
pH Value
6.5 - 7.5
Water type
Freshwater
Tank level
Bottom
Adult size
20 cm
Minimum tank volume
>= 180 L
Minimum group
>= 1
GH
2 - 8 dGH
KH
1 - 4 dKH
TDS
40 - 160 ppm
Conductivity
63 - 250 uS/cm
Species description
Geographic Origin and Biotope: FishBase records Retroculus lapidifer from the Amazon River basin and the Tocantins and Capim river basins in Brazil. It records the species as freshwater, benthopelagic and tropical, with a temperature of 22–27 °C.
Taxonomy and Morphology: FishBase records maximum lengths of 19.5 cm SL for male/unsexed specimens and 25.1 cm SL for females.
Social Behaviour: This recovery makes no statement about social behaviour.
Colouration and Sexual Dimorphism: This recovery makes no statement about colouration or sexual dimorphism beyond the separately recorded maximum lengths.
Care, breeding and tankmates
FishBase records Retroculus lapidifer as a freshwater, benthopelagic tropical species with a recorded temperature of 22–27 °C. Its listed distribution is the Amazon River basin and the Tocantins and Capim River basins in Brazil. The listed maximum lengths are 19.5 cm SL for male/unsexed specimens and 25.1 cm SL for females.
Geographic Origin and Distribution
This species originates from: Sud America (Bacino dei fiumi Araguaia e Tocantins, Brasile).
Origin
Amazon, Orinoco, and Guianas
Fish profile
- Temperament
- Semi-aggressive
- They are generally peaceful towards mid-water swimmers but highly territorial towards other bottom-dwellers. They display fascinating earth-moving behaviors that can constantly reshape the aquarium landscape. They require a specialized setup to exhibit their true, active nature.
- Diet
- Omnivore
- They are specialized benthivores that sift through the substrate for aquatic insects and crustaceans. In the aquarium, they require a diet of high-quality sinking cichlid pellets. Offering frozen bloodworms and krill simulates their natural diet perfectly.
- Life expectancy
- 5-8 years
- This rheophilic cichlid has an average lifespan of 5 to 8 years in a well-established home aquarium. Reaching this biological milestone requires strict management of water quality and the complete absence of nitrogenous waste, to which they are highly sensitive. Providing a balanced diet and a low-stress environment is fundamental to ensuring their long-term survival.
- Adult size
- 20 cm
- The catalog's scalar value is 20 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 25.1 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Retroculus lapidifer (v25.04); female 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
- Solitary
- Keeping them in a small group allows a natural pair to form. Once paired, the rest of the group may need to be removed to prevent severe aggression. Single specimens can also thrive without a mate.
- Feeding frequency
- Twice daily
- Feed them moderate amounts twice a day. They feed by scooping up sand, so ensure food sinks directly to the bottom. Overfeeding should be avoided to prevent rapid water quality deterioration.
- Bioload
- This is a robust, rheophilic cichlid that produces a substantial bioload. Their messy eating habits and size require heavy-duty filtration. Frequent, large water changes are mandatory to maintain the pristine water quality they demand.
- Flow
- Stagnant
- They absolutely require strong, highly oxygenated water flow simulating fast rapids. High-turnover canister filters and multiple powerheads are essential for their health. Without powerful flow, they will become lethargic and susceptible to disease.
- Reproduction
- Oviparous
- They are unique pit-spawners that dig deep nests in the substrate, usually behind rocks. Both parents vigorously defend the nest and the fry against intruders. Breeding requires highly oxygenated water and a specific diet conditioning.
- Compatibility & tankmates
- They are relatively peaceful for cichlids but are highly specialized. They can be kept with other rheophilic species like medium-sized plecos and fast-swimming tetras. Small bottom-dwellers might be aggressively chased away from their feeding territories.
- Tank level
- Bottom
- They are strict bottom-dwellers that spend their entire day interacting with the substrate. A fine sand substrate is absolutely critical to prevent damage to their delicate gills. They will rarely venture into the middle or upper water column.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 3.5 ± 0.3 se
- Resilience
- Medium (1.4 - 4.4 years)
- Phylogenetic uniqueness (PD50)
- 0.625
- Bayesian Length-Weight
- a = 0.0182, b = 3.06
- VulnerabilityLow vulnerability (21 / 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.
