Polypterus bichir Care Guide
Polypterus bichir is the Nile bichir, the largest commonly kept bichir and an obligate air-breather requiring a very large tank.
Compiled by Aquairi from published sources · Published · Updated
Overview
Polypterus bichir, the Nile bichir, was described by Lacépède in 1803. It is the largest bichir commonly kept by aquarists and is distributed from the Nile River through the Congo Basin to West African countries such as Senegal. Its body is dark grey above with darker vertical markings and bands on the flank.
Taxonomy
- Family: Polypteridae
- Genus: Polypterus
- Scientific name: Polypterus bichir
- Described by: Lacépède, 1803
- Common name: Nile Bichir
Habitat
According to Wikipedia, the species lives in the deeper depressions of muddy riverbeds and hunts in vegetated shallows, travelling mostly at night. In poorly oxygenated water it is an obligate air-breather and can drown without access to the surface.
Tank requirements
- Minimum tank volume: 1000 L
- Maximum size: up to about 75 cm body length (excluding caudal fin); KB range 70-90 cm
- Temperature: 24-28 °C (75-82 °F)
- pH: 6.5-7.8
- GH: 5-20 °dGH
- Lifespan: 15-30 years
- Surface access and a secured lid are both essential
Diet
According to Wikipedia, Polypterus bichir uses suction-feeding to capture prey and hunts aquatic and terrestrial invertebrates, fish and amphibians, eating fish up to half its own size.
Compatibility
The species is semi-aggressive and bottom-dwelling. It is best kept alone or with large catfish; smaller fish are at risk of being eaten.
Breeding
Breeding is rated advanced and is uncommon in home aquaria.
Conservation status
IUCN Red List: Least Concern (reassessed 2020).
Breeding the Nile Bichir (Polypterus bichir)
Overview
The Nile Bichir (Polypterus bichir) is the largest commonly kept bichir, reaching about 74 cm TL and roughly 2.7 kg. It is an essentially piscivorous, facultative air-breathing fish; the nominal subspecies is known from the Chad basin, Nile River basin and Lake Turkana, the other from the Senegal, Gambia, Geba, Volta and Niger rivers (FishBase). Polypterids have rarely bred in captivity (Wikipedia), and the adult size of P. bichir makes it impractical for the home aquarium.
Sexing
As in other Polypterus, the clearest external difference is the anal fin: mature males develop a broader, thickened anal fin that forms a cup during fertilisation, while females are typically larger-bodied (Wikipedia).
Conditioning
Polypterid spawning is tied to the rainy season and changes in temperature and water chemistry. Conditioning means well-fed adults in a very large system, followed by simulated seasonal change; the conductivity is lowered with cooler, softer water before temperature is raised (genus accounts, Wikipedia).
Spawning Behavior & Trigger
Spawning in Polypterus involves the male cupping his anal fin beneath the female to catch and fertilise eggs as they are released (Wikipedia). The trigger is imitation of the rains - generous water changes with soft, cool water that drop conductivity, followed by a temperature increase.
Egg & Fry Care
FishBase reports that in P. bichir the eggs are deposited in weeds, where the adult fish guards the eggs and young - parental care that is unusual within the genus. Eggs are slightly adhesive and stick to vegetation; polypterid larvae hatch with branched external gills resembling those of salamander larvae, which are lost with growth (genus account, Wikipedia).
Common Challenges
The species' large size demands enormous volumes to house breeders and to simulate a flood cycle. Pair compatibility, the rarity of any home success, and the difficulty of recreating seasonal cues make this an advanced, essentially commercial project.