Nothobranchius rachovii

Common Name

Bluefin Notho, Rachow’s Killifish

Origin and Habitat

Nothobranchius rachovii is native to the floodplains of Mozambique and parts of southern Africa, particularly around Beira and the lower Zambezi region. During the wet season, they inhabit shallow pools, ditches, and temporary floodwaters that are rich in vegetation and micro-life. These environments are typically warm, sunlit, and still, with muddy or sandy bottoms and abundant leaf litter. When the rains recede, these pools shrink into smaller pockets of water, creating ideal breeding grounds for this brilliantly colored killifish. The water in their native range is generally soft and slightly acidic to neutral, with minimal flow and a rich layer of organic material.

Temperature and Water Conditions

In the wild, Nothobranchius rachovii lives in warm, shallow pools that range from 68–77 °F (20–25 °C) during the wet season. The pH in these habitats typically falls between 6.0 and 7.2, and the water is naturally soft to moderately hard, depending on rainfall and soil type. In aquariums, maintaining clean, stable water and gentle flow is more important than adjusting chemistry. Frequent partial water changes and good aeration will help them thrive.

Appearance and Size

Males reach about 4–6 cm (1.5–2.4 inches) and are among the most striking freshwater fish available. They display a dazzling palette of turquoise, red, and orange across the body and fins, often with intricate striping and iridescence that shifts with the light. Females are smaller and more subdued in color, ranging from beige to light tan, providing contrast to the vibrant males. The species’ compact size and dramatic coloration make it a showpiece in smaller aquariums.

Diet in the Wild

In the wild, Nothobranchius rachovii feed on tiny aquatic invertebrates such as mosquito larvae, daphnia, worms, and micro-crustaceans found among the leaf litter and substrate. Their hunting instinct is well-developed, and they constantly search for moving prey in the shallows.

Feeding in Captivity

In the aquarium, they eagerly accept live and frozen foods such as bloodworms, brine shrimp, daphnia, and tubifex. High-quality micro-pellets and flake foods can be used once they are acclimated, but live and frozen foods will bring out their best coloration and activity. Small, frequent feedings replicate their natural feeding rhythm and help maintain excellent condition.

Behavior and Tank Setup

Bluefin Nothos are energetic and engaging fish with clear personalities. Males can be territorial, especially in smaller tanks, so it’s best to keep one male with two or more females or maintain a group in a larger, well-decorated species setup. They are peaceful toward other gentle fish and do well in quiet community tanks if tankmates share similar needs. Provide a soft, fine substrate such as sand or peat for natural foraging and spawning behavior. Add floating plants to diffuse light and include driftwood or roots to create shaded resting spots. A tight-fitting lid is essential since they can jump when startled.

A 10–20 gallon aquarium is adequate for a small group, but larger tanks allow for more natural behavior and better stability. Maintain gentle filtration, strong oxygenation, and stable water parameters.

Breeding

Breeding Nothobranchius rachovii is one of the most fascinating experiences in the hobby. Pairs spawn readily in fine sand or peat moss substrate, where females deposit eggs that are slightly adhesive and settle into the material. In nature, the eggs endure a period of dry dormancy until the rains return, but in aquariums, they can also develop continuously in damp peat if kept properly. Conditioning the adults with live foods and providing a soft substrate often leads to spontaneous spawning.

After a few weeks, remove the peat containing eggs and keep it moist in a sealed bag or container at room temperature. When re-wetted with soft, slightly cooler water, fry hatch within 24–72 hours. Newly hatched fry are small and should be started on infusoria, green water, or liquid fry food, followed by microworms or baby brine shrimp as they grow. With good feeding and clean water, they develop color quickly and become sexually mature within a few months.

Quick Facts

Scientific Name: Nothobranchius rachovii
Common Names: Bluefin Notho, Rachow’s Killifish
Origin: Mozambique and Southern Africa
Maximum Size: 4–6 cm (1.5–2.4 inches)
Temperature: 68–77 °F (20–25 °C)
pH: 6.0–7.2 (soft to moderate hardness)
Temperament: Peaceful, active
Diet: Carnivore – small live and frozen foods
Breeding: Substrate spawner

Tropical Fish Co. Notes

If you’re looking for a fish with a wow factor, Nothobranchius rachovii absolutely delivers. The males are vivid, active, and commanding in their small aquarium world. They bring rapid development, distinct personality, and breathtaking colour to any setup. We recommend them for the dedicated hobbyist or a biotope-style aquarium rather than a general community tank. Provide soft substrate, ample live-food, and a modest footprint with strong personality, and you’ll be rewarded with an aquarium full of zest and activity. Because of their beautiful male colours, fast growth, and dramatic behaviour, they’re a standout pick for display tanks or as a special species project.