African Red-Eye Tetra (Arnoldichthys spilopterus)

The African Red-Eye Tetra (Arnoldichthys spilopterus) is a lively and attractive characin native to the lower Niger River delta and surrounding coastal river systems of Nigeria and surrounding regions. Unlike the majority of popular tetras which hail from South America, this species represents the African continent's rich characin fauna and brings a distinctly different aesthetic to the community aquarium.

Adult specimens reach approximately 6–7 cm and display beautiful golden-green iridescence along the flanks, a bold black lateral stripe, and the species' most recognisable feature: a brilliant red upper iris that gives the fish its common name. Males tend to be more colourful, while females are noticeably rounder in the belly, especially when in spawning condition.

In the wild, Arnoldichthys spilopterus inhabits medium to fast-flowing rivers and streams with clear to slightly tannin-stained water. It is a surface-oriented species, feeding primarily on insects and other invertebrates that fall onto the water surface. In the aquarium, it readily accepts floating flake and pellet foods, live and frozen insects, and other high-protein foods.

The African Red-Eye Tetra is a schooling species that does best in groups of eight or more. When properly grouped, it puts on impressive displays of synchronised swimming. A tightly-covered aquarium is essential as this species is an accomplished jumper. It is compatible with most robust community fish of similar size.

Tank Setup: A minimum 120-litre aquarium (90 cm length) is recommended for a school of eight. Provide good open swimming space in the midwater with some planted edges and driftwood for contrast. Strong filtration with some current is appreciated. Ensure the tank has a tight-fitting lid — this species jumps readily.

Water Parameters: Temperature 24–28°C; pH 6.0–7.5; GH 5–15 °dH; KH 3–8 °dH. Adaptable to a range of conditions but prefers slightly acidic to neutral water. Avoid extremes.

Feeding: Omnivore with a preference for protein. Feed a mix of quality flake/micro pellets, frozen bloodworm, Daphnia, brine shrimp, and where possible, live insects like fruit flies. Feed twice daily in portions consumed within two minutes.

Tank Mates: Suitable with similarly sized, robust fish: Congo tetras, medium rainbowfish, Synodontis catfish, barbs, and peaceful cichlids. Avoid fin-nipping species and very slow, long-finned fish as tank mates.

Behaviour: Active and fast-moving schooling fish. Kept in groups of 8+, they school beautifully and pose no threat to other species. Males may chase each other briefly but this is rarely harmful.

Health: Hardy and adaptable once established. Prone to stress if kept in small numbers or poor water quality. Maintain weekly water changes of 25–30% and ensure excellent oxygenation.