Nanochromis parilus

Nanochromis parilus is widespread in the Congo River basin, occurring in calm, slow-moving sections with sandy and rocky substrates. Males develop a distinctively lyrate caudal fin — the upper and lower lobes are elongated and edged in red — while the body is a pleasing silvery-olive green with subtle blue iridescence on the flanks. Females are smaller and rounder with a violet-tinted belly when in condition.

The species is a cavity-spawner: eggs are deposited deep within a rock crevice or under a flat stone, and both parents participate in defence of the clutch and subsequent care of the free-swimming fry. Water quality must be consistently good — Nanochromis species are sensitive to nitrate accumulation, so regular partial water changes are important.

Soft, slightly acidic to neutral water at 24–27°C suits N. parilus well. A sandy-bottomed tank with flat rocks, smooth driftwood, and moderate planting reflects the natural riverine habitat and supports natural behaviour.