贡氏假鳃鮰 · Gunther's Nothobranch

Overview

Endemic to Unguja, Nothobranchius guentheri survives seasonal habitat loss through eggs in the mud. It is often chosen for a first attempt at annual killifish breeding, but maintaining a line requires egg storage and fry rearing rather than relying on long-lived adults.

Distribution & habitat

It is native only to Unguja, the main island of Zanzibar. Coastal lowland pools and marshes fill during rain and dry completely later. Their water is often turbid, and agricultural drainage or conversion to rice fields threatens some sites.

Aquarium setup

Allow at least a 45 by 30 cm footprint for one male with two or three females. Dark soft substrate, dense plants, floating cover, and wood create retreats under subdued light. Use a secure lid and gentle filtration, such as an air-driven sponge unit.

Diet & feeding

Base feeding on live or frozen small invertebrates. Most fish take dry foods only occasionally, so these should not be the sole planned diet.

Behaviour & compatibility

A species aquarium is preferable. Males fight, so keep only one unless sufficient room allows separate territories. Two or three females per male distribute persistent courtship pressure.

Sexual dimorphism

Males are larger and blue-green, with red oblique gill-cover bars and a red tail edged black at the rear. Smaller yellow-brown females lack those markings.

Breeding

Condition the sexes separately, then spawn a male and two females over peat. Although spawning can continue for weeks, return the breeders to conditioning after about a week to avoid exhausting females.

Remove the peat, dry it until damp rather than wet, and seal it in a labeled bag. Accounts commonly use 8–14 weeks of storage; premature wetting can produce weak fry. Place the peat in shallow rearing water to hatch it. If few eggs hatch, another few weeks of dry storage followed by rewetting may suit the slower-developing eggs.

Begin fry on infusoria, introducing Artemia nauplii or microworms after about two days and larger foods around two weeks. Increase depth gradually and make small water changes every two or three days, as fry are prone to velvet disease.

Notes

Past confusion with related fishes makes identity checks useful. The male red tail with its black rear edge and unmarked females provide practical clues. Its small native range and disappearing seasonal pools reinforce the value of preserving locality information.