Care guide · Freshwater · fish

Egger’s notho

Nothobranchius eggersi

Male Nothobranchius eggersi. Photo: Violaine2, CC BY-SA 3.0 (resized proportionally). Photo: Violaine2 / Wikimedia Commons · Source · CC BY-SA 3.0; GFDL 1.2 or laterProportional PNG-to-JPEG conversion only; no crop or colour adjustment. CC BY-SA attribution/license and GFDL alternative retained.

Egger’s notho (Nothobranchius eggersi) is a colourful annual killifish from eastern Tanzania. Males occur in red and blue colour forms, with the dominant hue and intensity varying among populations. Females are smaller and much less vivid. In temporary pools, eggs survive the dry season in the substrate. This biology calls for a deliberate housing and breeding plan. The specialist care source advises against a community aquarium. Keep provenance codes for captive lines separate: these codes refer to population origin, not merely a colour variety. The BKA lists the species as Least Concern, but that is not a substitute for local conservation. Never release aquarium fish or breeding material.

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At a glance

Temperature: 20–24 °C
pH: 7.0–8.2
GH: 10–30 °dGH
Aquarium length: At least 45 cm
Minimum aquarium volume: At least 41 L
Adult size: Up to 5 cm
Group size: At least 2 individuals
Temperament: Predator

About this species

The accepted name is Nothobranchius eggersi Seegers, 1982. It was described from a pool near the Ruhoi River in eastern Tanzania. Seriously Fish gives males at about 50 mm standard length; FishBase reports a maximum of 5.0 cm total length. These are different measurements. Males show striking red or blue patterns, whose intensity varies among populations. Females are smaller and plain. Hobbyists use locality codes, often encoding country, year and collection site. Keep these lines separate because crossing can erase population differences. Do not treat a red or blue aquarium strain automatically as a verified natural population.

Natural habitat

Nothobranchius eggersi inhabits temporary pools and swamps on lowland floodplains in eastern Tanzania. Confirmed distribution includes the lower Rufiji area and nearby river systems; the type locality is near the Ruhoi. Shallow depressions fill during the rains, then water levels fall and pools disappear in the dry months. Adults do not survive this; eggs in the substrate can enter a resting phase until water returns. FishBase reports 24–28°C for natural waters, while captive guidance is cooler. Field measurements are not a maintenance recipe. In an aquarium, stable water quality, calm conditions and cover are more useful than literally recreating desiccation.

Aquarium and layout

For a pair, Seriously Fish recommends a base of at least 45 × 30 cm and about 41 litres; volume depends on height. Use a secure lid because killifish can jump. Dense plants, floating cover and wood provide shelter and break sightlines. Soft substrate or a separate spawning medium can support breeding, but Seriously Fish says peat is not required for routine maintenance. Keep flow controlled and biological filtration mature. Treat this as a species aquarium: the specialist source says it is not a community fish. Plan rearing space and appropriately sized food for fry before breeding.

Water conditions

Seriously Fish recommends 20–24°C, pH 7.0–8.2 and GH 10–30 °dGH for aquarium care. FishBase reports 24–28°C in natural waters. These values describe different contexts; use the aquarium range rather than raising temperature to match a field reading. Keep temperature and pH stable and test your source water. The hardness range is specialist care guidance. Acclimate gradually and avoid waste accumulation. Do not routinely add salt, peat extract or pH buffers. Some breeders use salt to reduce Oödinium risk in fry, but Seriously Fish presents this as a practice used by some aquarists, not a universal requirement.

Behaviour and group size

Seriously Fish gives pair housing and says this is not a community fish. That does not guarantee every pair will be trouble-free: watch for chasing, damaged fins and feeding competition. Provide cover and escape routes for females. Small prey animals, fry and shrimp may be at risk from this micropredator. No particular tankmates have been confirmed as safe, so this guide recommends none. Keep locality codes separate and do not mix red and blue lines without reliable provenance and a deliberate breeding goal. Check daily that both fish are eating and that neither is persistently harassed.

Feeding

This is a micropredator that feeds mainly on small live or frozen invertebrates. Seriously Fish lists Daphnia, Artemia and finely chopped bloodworm. Offer small portions eaten promptly and rotate suitable prey. Dried food may be supplementary only if you observe acceptance; a source’s list of dried prey does not make every dry food a complete staple. Remove leftovers to limit pollution. Match particle size to the mouth and life stage. The current central catalogue has no verified suitable staple product for this micropredator, so no arbitrary product link is added.

Breeding

Fish deposit eggs in substrate; the eggs can withstand a dry incubation period. The BKA gives about eight weeks at 24°C as a guide, while Seriously Fish describes 3–4 months of storage around 21–25°C. This difference shows that timing varies with line and conditions. Keep spawning medium moist, not wet, and label species, population code and date; inspect eggs before re-wetting. The BKA says fry may take newly hatched Artemia nauplii immediately and can mature in five to six weeks; Seriously Fish cautions that fry are small and may need infusoria. Prepare first foods and rearing space, and do not breed without a responsible plan for offspring.

Sources & review

This care guide draws on several specialist sources and was last checked on 17 October 2026.

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