Nothobranchius guentheri Care Guide
Nothobranchius guentheri, the redtail notho, is an annual killifish endemic to Zanzibar and one of the longest-known species in the hobby.
Compiled by Aquairi from published sources · Published · Updated
Overview
Nothobranchius guentheri, the redtail notho, is an annual killifish of the family Nothobranchiidae. It was originally described by Pfeffer in 1893 as Fundulus guentheri and is named after the ichthyologist Albert Günther. Males show iridescent blue scaling with reddish unpaired fins. It is endemic to Zanzibar.
Taxonomy
- Family: Nothobranchiidae
- Genus: Nothobranchius
- Scientific name: Nothobranchius guentheri
- Author: Pfeffer, 1893
Habitat
FishBase records the species as endemic to Unguja Island in the Zanzibar archipelago, eastern Tanzania, where it inhabits temporary pools, swamps, ditches and small streams. These waters fill during the rains and dry seasonally, so the fish completes its life cycle within a single wet season.
Tank requirements
- Minimum tank volume: 40 L
- Temperature: 22-26 °C (72-79 °F)
- pH: 6.5-7.5
- GH: 5-15 °dGH
- Adult size: 5-7 cm
- Lifespan: 1-2 years
Diet
The species is a carnivore. In the hobby it takes live and frozen foods such as bloodworm, Daphnia and brine shrimp, fed about twice daily.
Compatibility
Males are territorial toward one another, so the species is best kept as a single male with several females in a quiet species tank. It should not be combined with boisterous community fish.
Breeding
Nothobranchius guentheri is an egg-burying bottom spawner. FishBase reports rapid development, with fish becoming sexually mature in only 6 to 8 weeks, and an egg incubation period of about 3 to 4 months in moist substrate before hatching when re-wetted.
Guenther's Nothobranchius (Nothobranchius guentheri) Breeding Guide
Overview
Nothobranchius guentheri is an annual killifish endemic to Zanzibar, where it inhabits intermittent rivers and seasonal freshwater marshes that dry up each year. It has been kept in the hobby for over a century. In the wild it feeds on mosquito larvae and other planktonic creatures, and its eggs persist in the substrate after the adults die when their pools evaporate.
Sexing
Males show iridescent blue scales with brick-red unpaired fins, while females are smaller and a uniform grey-brown. The strong dimorphism makes pairing simple; keep one male with several females.
Conditioning
As a carnivore it should be conditioned on small live and frozen foods including mosquito larvae, daphnia and bloodworm. Heavy feeding keeps females spawning daily over the peat.
Breeding Setup
Provide a small species tank with a container of soft peat for the fish to spawn into. The peat spawner habit means pairs repeatedly push into the substrate to bury eggs. Gentle filtration and low light keep the group settled and productive.
Spawning Behavior & Trigger
Pairs or small groups spawn by repeatedly pushing into the substrate and releasing and fertilising a single egg at a time. After spawning the peat is collected and gently squeezed to a damp consistency before storage.
Egg Diapause & Hatching
Specially adapted chorion proteins retain moisture in the eggshell, allowing the eggs to survive the dry season. Eggs have a dry incubation of between 8 and 12 weeks, with most hatching after about 9 weeks. When water returns, the fry detect the pressure change of submersion and a rise in dissolved carbon dioxide, which triggers release of the enzyme chorionase to soften the shell for hatching. Flood the damp peat with soft, cool water to hatch a batch.
Common Challenges
If the incubation period or moisture is off, eggs may not respond to the first wetting; re-drying the peat and wetting again often recovers them. Weak fry that cannot leave the bottom, known as belly-sliders, indicate over-rapid or poorly timed hatching.