Polypterus palmas Care Guide
Polypterus palmas is a medium West African bichir with marbled flanks, a hardy nocturnal predator that hunts by smell.
Compiled by Aquairi from published sources · Published · Updated
Overview
Polypterus palmas, the shortfin or marbled bichir, was described by Ayres in 1850. It is found in freshwater across West Africa, including Ghana, the Democratic Republic of the Congo, Cameroon, Liberia, Guinea, Ivory Coast and Sierra Leone. Two former subspecies are now considered colour morphs rather than valid taxa.
Taxonomy
- Family: Polypteridae
- Genus: Polypterus
- Scientific name: Polypterus palmas
- Described by: Ayres, 1850
- Common name: Shortfin Bichir
Habitat
According to Wikipedia, the species inhabits freshwater demersal environments and in captivity prefers soft, slightly acidic water with shaded hiding places. It shows bright gold colour, a speckled pattern and dark transverse barring; southern populations are paler with thinner bars while northern ones are deeper gold with thicker barring.
Tank requirements
- Minimum tank volume: 250 L
- Maximum size: up to about 35 cm (the largest recorded was 35.3 cm); usually around 30 cm
- Temperature: 24-28 °C (75-82 °F)
- pH: 6.5-7.8
- GH: 5-20 °dGH
- Lifespan: 10-18 years
- A tight, secured lid is essential as bichirs jump
Diet
According to Wikipedia, Polypterus palmas is an opportunistic predator that consumes frozen or live foods such as bloodworms or earthworms and may eat small tankmates. It hunts using its lateral line and sense of smell rather than vision.
Compatibility
The species is semi-aggressive and bottom-dwelling. It can share a tank with robust companions such as larger Synodontis and mid-sized cichlids; tiny fish should be avoided.
Breeding
Breeding is rated advanced and is uncommon in home aquaria.
Conservation status
IUCN Red List: Least Concern (assessed 2021).
Breeding the Shortfin Bichir (Polypterus palmas)
Overview
The Shortfin Bichir (Polypterus palmas) is a medium West African polypterid reaching about 35 cm SL. It is a freshwater, bottom-dwelling, facultative air-breather from coastal rivers of the Gulf of Guinea, from Guinea-Bissau to Liberia and the upper Casamance and Cavally rivers, and is listed as Least Concern by the IUCN (FishBase). As with all bichirs, captive breeding is rare (Wikipedia).
Sexing
The reliable external cue across Polypterus is the anal fin, which is noticeably broader and thicker in mature males because it forms a cup used to direct and fertilise eggs (genus account, Wikipedia).
Conditioning
Reproduction in bichirs is tied to the rainy season and to shifts in temperature and water chemistry. Adults are conditioned on meaty foods, then exposed to simulated seasonal change. The smaller adult size of P. palmas makes housing breeders more feasible than for the giant species, though success remains uncommon.
Spawning Behavior & Trigger
A ripe male cups his anal fin beneath the female to catch and fertilise eggs as they are released (genus account, Wikipedia). The recognised trigger is imitation of the rains: generous water changes with soft, cool water that lower conductivity, followed by a rise in temperature.
Egg & Fry Care
Eggs are slightly adhesive and adhere to plants. Polypterid larvae hatch bearing branched external gills like those of salamander larvae, which regress as the fry grow (genus account, Wikipedia). Bichirs do not generally guard their spawn, so eggs and fry should be separated from adults.
Common Challenges
Even at this smaller size, reliably forming pairs, recreating the seasonal flood cue and protecting eggs and larvae from predation are the main hurdles, and documented home spawnings remain scarce.