Redtail Notho Care Guide - Aquarium Setup, Diet & Breeding

The Redtail notho is a small, brilliantly coloured annual killifish with a compact body and an expressive, slightly upturned mouth. Mature males develop a deep blue to blue-green base colour, vivid red markings on the fins and body, and especially striking red-orange in the tail. Females are much plainer, usually appearing silvery beige or olive with translucent fins.

Males are active, confident fish that display to one another and compete for access to females. They can be territorial in a confined aquarium, particularly when several males are kept together, while females are generally more peaceful. Their bold colours and lively courtship behaviour make them a fascinating subject for a species aquarium.

In nature, Redtail nothos inhabit shallow seasonal pools, floodplain depressions and temporary bodies of water that may exist for only part of the year. The fish mature rapidly, reproduce during the wet season and leave drought-resistant eggs in the substrate before the pools disappear.

Nothobranchius guentheri has become one of the best-known killifish in the aquarium hobby. Its short adult lifespan is closely connected to its annual life cycle, although good conditions and careful husbandry can help captive fish live longer than their wild counterparts.

Redtail nothos are native to seasonal pools and temporary wetlands in coastal East Africa, particularly Tanzania and the island of Zanzibar, with related populations reported from nearby parts of Kenya. These habitats regularly dry out, which explains the species’ remarkable annual breeding cycle.

A minimum aquarium of around 40 litres is suitable for a small group, with a footprint of approximately 60 x 30 cm preferred over a tall tank. Use a secure lid because these fish can jump, gentle filtration and subdued lighting. Dark sand or fine gravel helps show off their colours, while dense plants, floating vegetation, spawning mops and other visual barriers provide cover for females and reduce male confrontation. Leave an open area for swimming and use stable, mature decor rather than sharp ornaments.

Males reach about 5 cm (2 inches) in length, while females are smaller at approximately 4 cm (1.6 inches).

These carnivorous killifish thrive on a varied diet of live and frozen foods. Offer suitably sized daphnia, brine shrimp, bloodworms, mosquito larvae and other small aquatic invertebrates. Live foods are especially useful for conditioning adults for breeding, while high-quality frozen foods can form part of the regular diet. Feed small portions frequently and remove uneaten food promptly.

Redtail nothos are best kept in a dedicated species aquarium or with other peaceful, similarly sized fish that will not outcompete them for food. Suitable companions can include small, calm rasboras, peaceful tetras and gentle dwarf corydoras in a suitably sized aquarium, although a species-only setup is usually the simplest choice. Avoid large or aggressive fish, persistent fin-nippers and other annual killifish, and provide plenty of cover if more than one male is kept.

Redtail nothos are annual killifish that scatter eggs into a soft peat or spawning-mop substrate. Provide a breeding tank with one male and two or three females, then collect the eggs and store them in damp, not wet, peat at room temperature. Depending on the strain and conditions, the eggs usually need several weeks to a few months of incubation before being placed in shallow water to hatch. Fry grow quickly and should receive tiny live foods immediately, with frequent feeding and water changes.

Males are larger and much more colourful, with blue-green bodies, red markings and red-orange fins. Females are smaller and predominantly silver, beige or olive with comparatively clear fins.