Bluefin Notho Care Guide - Aquarium Setup, Diet & Breeding

The Bluefin Notho is one of the most striking annual killifish, with mature males displaying a vivid blue body, red markings and richly coloured fins. Depending on mood and locality, the blue may range from turquoise to deep metallic cobalt, while the red patterning can be especially intense across the flanks and tail.

Males are active, competitive and eager to display, particularly around females and rival males. Females are much more discreetly coloured, usually golden brown or olive with subtle markings. Although small, these fish have a lively presence and are fascinating to observe during courtship and feeding.

In nature, Bluefin Nothos inhabit temporary pools that fill during seasonal rains and gradually evaporate during the dry season. The species is adapted to this demanding cycle by producing eggs that can remain dormant in damp substrate until the next suitable period of flooding.

Their natural life cycle is short compared with that of many familiar aquarium fish, but this is part of their appeal to killifish enthusiasts. The scientific name is Nothobranchius rachovii, and captive-bred strains may differ noticeably in colour, pattern and adult size.

Bluefin Nothos are native to seasonal freshwater pools and floodplain habitats in Mozambique, particularly around the lower Zambezi region in southeastern Africa. Their pools dry out periodically, so the species survives between wet seasons as dormant eggs in the substrate.

A pair or small trio should have at least 40 litres of water, with a footprint of approximately 60 x 30 cm or larger. Use a secure lid because these fish can jump, and keep the water movement gentle. A dark, fine substrate or bare-bottom breeding setup works well, with clumps of Java moss, floating plants, fine-leaved stems and other subdued cover. Include a container of peat or another suitable spawning medium when breeding. Soft, slightly acidic to neutral water, subdued lighting and shaded areas help replicate their seasonal pool habitat.

Males reach up to about 6 cm (2.4 inches) in total length, while females are usually smaller at around 4.5–5 cm (1.8–2 inches).

Bluefin Nothos thrive on a varied, protein-rich diet. Offer small live foods such as baby brine shrimp, daphnia, mosquito larvae, grindal worms and blackworms, supplemented with suitable frozen foods. Live foods are particularly valuable when conditioning adults for breeding and help bring out their best colour. Feed small portions regularly and remove uneaten food, as these fish can be sensitive to deteriorating water quality.

Bluefin Nothos are best kept in a species-focused aquarium, either as a male with several females or in a carefully managed group. They can sometimes live with other peaceful, similarly sized killifish or calm small African species, but mixing strains or closely related Nothobranchius can lead to hybridisation. Avoid fin-nipping fish, boisterous tankmates, large predators and very active community species that will outcompete them for food. Males may be territorial, so provide plenty of cover and avoid overcrowding.

Bluefin Nothos are annual killifish that scatter their eggs among peat or another soft spawning medium. Provide a breeding tank with clean, shallow water and condition the fish generously with live foods. A male can be kept with two or more females to spread courtship pressure. Collect the eggs from the spawning medium, store them in damp peat at room temperature, and check them after roughly three to six months. When the embryos are fully developed and show clear eyes, flood the peat with cool, clean water to hatch the fry. Feed the tiny fry immediately with infusoria or another suitably small first food, followed by baby brine shrimp as they grow.

Males are larger and dramatically coloured, with metallic blue bodies, red markings and more extended, ornate fins. Females are smaller and comparatively plain, usually appearing brownish, olive or golden with less prominent patterning.