Nanochromis Parilus

Geographic Origin and Biotope: Lower Congo River Basin (Central Africa), endemic to the Inga and Bulu rapids. Inhabits exclusively the tumultuous currents that flow over smooth rocks, basalt crevices and compact sand.

Taxonomy and Morphology: Nudiceps Cichlid (Nanochromis parilus, often confused with N. nudiceps). Rheophilic dwarf cichlid (lover of currents). Presents an incredibly elongated and dorso-ventrally flattened body to avoid the thrust of the water, with a flat belly.

Social Behavior: Territorial digger. Despite being a dwarf (7 cm / 2.8 inches), it protects a vital radius on the bottom (cave and attached boulders) furiously attacking any bottom fish that passes within range. Must form a pair otherwise the male will persecute the female.

Coloration and Sexual Dimorphism: Magnificent. Iridescent metallic/silvery background color. Females are the show: they possess a bright and enormous pink-purplish belly (when pregnant) which they curve to attract the mate, and the upper half of the tail striped like a chessboard (different from nudiceps). The male is larger but less colorful.

Aquarium Setup: Rheophilic Aquarium (river style, minimum 80-100 cm / 32-40 inches). Rounded calcareous sand and lots of smooth stones, stacked to form small caves. VERY IMPORTANT: a wavemaker or powerful powerhead that creates a violent unidirectional current close to the bottom.

Diet and Feeding: Insectivorous micropredator. Tirelessly nibbles sand and rocks in search of larvae and crustaceans. Sinking feeds (discus pellets, carnivorous granules, bloodworms) must fall quickly to the bottom.

Water Quality: Requires the oxygenation of a torrent. While tolerating neutral pH, if the water is stagnant (slow filters, zero wavemakers), they will collapse gasping and die of asphyxiation.

Compatibility and Tankmates: Good companion to very fast African Tetras or current Cyprinids (Phenacogrammus, Danios). NEVER insert Corydoras, Loricariids or other dwarf Cichlids (e.g. Pelvicachromis or Steatocranus) which would be brutalized by the pair at the bottom level.

Aquarium Reproduction: Cave spawners. The female frantically digs a den (removing shovelfuls of sand). After laying in the roof of the cave, the male patrols the outer perimeter, while the mother incubates. Extreme parental care for a month.

Risks and Diseases: Couple War and Collapses. If the couple quarrels, the male will try to kill the female if there are not enough hiding places. Watch out for unstable rocks: Nanochromis is such a digger as to cause landslides; the stones MUST rest on the glass, not on the sand.