Product Details

Rachow’s Notho – Nothobranchius rachovii

The Rachow’s Notho is a spectacular annual killifish known for its intense blue, red and orange male colouration and short but fascinating life cycle. Also sold as the Bluefin Notho, Rachow’s Killifish or Rachow’s Nothobranch, this species is best suited to specialist killifish aquariums rather than standard community tanks. It is colourful, active and highly rewarding, but it needs soft water, calm conditions, careful feeding and an understanding of annual killifish breeding.

Key Identification:

Common Name: Rachow’s Notho
Other Names: Bluefin Notho, Rachow’s Killifish, Rachow’s Nothobranch, Bluefin Nothobranch
Scientific Name: Nothobranchius rachovii
Fish Type: Annual Killifish
Water Type: Freshwater

Natural Range & Habitat:

Nothobranchius rachovii is native to East Africa, especially Mozambique and nearby floodplain regions associated with the lower Zambezi and Pungwe river systems. In the wild, it lives in temporary pools, seasonal swamps and shallow water-filled depressions that form during the wet season.

These habitats often contain grasses, aquatic vegetation and soft muddy substrate. As the dry season progresses, the water gradually disappears. Adult fish do not survive the dry period, but their eggs remain dormant in the substrate until rains return. In the aquarium, this annual life cycle is an important part of understanding the species.

Appearance & Adult Size:

Male Rachow’s Nothos are among the most colourful freshwater aquarium fish, with bright blue body colour, red-orange spotting, patterned fins and a vivid blue to orange tail. Colour and pattern can vary depending on population, strain and mood.

Females are much plainer, usually beige, grey or light brown with little strong colour. Adults usually reach around 5–6 cm, with males often appearing brighter and more showy, while females are softer in colour and slightly fuller-bodied when mature.

Aquarium Suitability:

This species is best suited to a small specialist killifish aquarium or a carefully managed species setup. It does not need a large tank, but it does need excellent water quality, peaceful conditions, soft cover and careful feeding.

Rachow’s Notho is not ideal for a general tropical community aquarium. Its short lifespan, breeding method, male competition and preference for calm tank mates make it better suited to aquarists who specifically want to keep annual killifish.

Recommended Aquarium Size:

A practical minimum is 30–40 litres for a trio or small breeding group, with more space useful if keeping multiple males.

A common setup is one male with two or more females. Males can be competitive, so avoid keeping multiple males together unless the aquarium has enough space, cover and visual barriers.

Water Conditions:

Temperature: 20–24°C
pH: 6.0–7.2
Hardness: Soft to moderately hard
Additional Notes: Keep water clean, stable and gently filtered. Avoid strong current, high temperatures and poor water quality. Peat, spawning mops or suitable spawning media may be used by experienced keepers for breeding. A secure lid is essential, as killifish can jump.

Temperament & Tank Mates:

Aquarium Category: Semi-Aggressive

Rachow’s Nothos are generally peaceful with unrelated fish, but males can be persistent with females and competitive with rival males. They are best kept as a species group rather than in a busy community aquarium.

If tank mates are used, choose very calm, small fish that enjoy similar soft, quiet water and will not outcompete them for food. Avoid fin-nippers, boisterous barbs, large predators, aggressive cichlids, fast-feeding community fish and any species that may harass males or stress females.

Feeding:

Rachow’s Notho is a small carnivorous micropredator. Offer live and frozen foods such as daphnia, cyclops, mosquito larvae, baby brineshrimp, adult brineshrimp, bloodworm and small whiteworm.

Many individuals may learn to take fine pellets or soft prepared foods, but dry food should not be relied upon as the only diet. A varied live and frozen diet is important for colour, condition and breeding success. Feed small amounts regularly and remove uneaten food to protect water quality.

Behaviour in the Aquarium:

This is an active lower to midwater killifish that explores planted cover, spawning media and open areas. Males display intensely, showing bright colour and flared fins when courting females or challenging rival males.

Breeding behaviour is a major part of keeping this species. Pairs or trios may dive into soft spawning media, where eggs are deposited. The eggs require a dry incubation period before being rewetted, reflecting the natural seasonal cycle of temporary pools.

Care Notes:

Rachow’s Notho is a specialist annual killifish and should not be bought as a standard community fish. It has a naturally short lifespan, often around 6–12 months, although this can vary with temperature, strain and care.

Provide a secure lid, calm filtration, soft cover and excellent water quality. Avoid high temperatures, as warmer conditions may shorten lifespan. If breeding, research egg collection, peat or fibre spawning media, dry incubation and fry feeding before purchase.

Recommended For:

Experienced

Availability:

Rare to occasional / Usually captive-bred by specialist killifish breeders or available as eggs

Image Disclaimer:

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Natural variation in size, colour, pattern, body tone and markings can occur between individual fish.