Aequidens diadema

Aequidens diadema, the diadem acara, is a medium-sized cichlid from the Vichada, Meta, and Amazon tributaries of Colombia and Venezuela. The species name 'diadema' (crown) refers to the dark band running across the nape that evokes a crown-like marking, complemented by the blue-green iridescent spangles scattered across the grey-olive flanks.

This is a moderately robust acara that occupies a middle ground between the relatively peaceful geophagines and more aggressive large cichlids. Pairs form stable bonds and are effective parents, guarding both eggs and free-swimming fry. They are more peaceful than many members of the genus when not breeding.

Aequidens diadema is rarely encountered in the hobby and makes an excellent subject for the aquarist interested in wild-type South American cichlids beyond the commonly kept species. A moderately large aquarium with ample territory and good filtration is sufficient for a pair.

Water: Temperature 24–27°C, pH 5.5–7.0, GH 2–10, KH 1–5; soft to moderately soft water preferred; weekly partial changes. Tank: 200 L minimum; sand substrate, driftwood, and robust plants; provide clear territory boundaries with rocks. Feeding: Omnivore; quality cichlid pellets, frozen bloodworm, brine shrimp, and occasional vegetable matter. Breeding: Open spawner on flat rocks or broad leaves; both parents guard eggs and fry actively. Compatibility: Suitable with medium to large robust South American species; avoid very small or timid tank mates.