fish difficult level

Polypterus palmas

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Marbled bichir, Shortfin bichir

Polypterus palmas will fieel at home in the biotope tank with soft substrate like sand decorated with pieces of driftwood and rounded rocks arranged to create some hiding places for the fish.

Distribution: West Africa: Upper Guinea region, Senegal to Ivory coast.

 

Submitted by
Natasha Khardina
GPS
2.1409450, 21.4618988
Geographical region
Cenral Africa
Drainage Basin
Congo River
River catchment
Water body type
Creek
Water body name
Nameless
Water body part
River mouth
Water body course
Lower course
Water body: tributary of
River
Tributary name
Congo
Type locality
Cape Palmas, Liberia.
Conservation status/IUCN Red List
Not Evaluated (NE)

Water Chemistry

Water information

Water type
Fresh water
Water color
Black water
Water transparency
Medium
Concentration of sediments
Low
Water temperature
25-28 °C
Water flow/curent
Slow

Chemical parameters

pH
6.0-7.0
Conductivity
GH
5-15 mg/l
KH
Dissolved Oxygen

Biology

Standard length
30 cm
Water volume (min. aquarium)
200 l
Social behaviour
Lives single
Behaviour description

No tankmates that can fit in its mouth, Polypterus palmas is relatively peaceful otherwise. Plants are not essential but are appreciated. It is suggested to cover the tank with tight-fitting glas or canopy of aquatic plants as this fish is known as an excellent escape artist.

Aggression grade
Peacefull
Activity
Night active
Sexual dimorphism

The main difference between adult male and female is that the males have a considerably broader anal fin. The immature specimens are difficult to distinguish. Males Polypterus palmas also tend to be smaller than females.

Nutrition in Nature

Carnivorous by nature.

Reproduction

Breeding tank set-up

Having a havily planted area in the tank might induce breeding. Once the female have found the suitable spawning site, she starts deposing the eggs.

Nutrition parents

Being a predator, in the aquarium Polypterus palmas usually don’t accept dried foods, but should have a varied diet of meaty live or frozen foods such as prawns, earthworms, mussel, lancefish.

Mating type
Monogamous
Spawning behaviour

Normally Polypterus palmas courtship lasts for 1-2 days, starting with the male chasing the female, bumping into her with his snout.

The female wdeposits several eggs each time, and the eggs are fertilized by the male when he cups his anal and caudal fins around the genital area of the female Bichir.

The male takes the eggs, fertilizes them and they are then scattered over the plants. An egg is 2-3mm and slightly adhesive. It will stick to the plants until the fry hatch. The parents should be removed from the aquarium as soon as the final fertilization is finished.

Breeding habits
Substrate-spawning
Hatching period
3-4 days
Number of eggs in average
100-300
Parental care
No
Fry number
Variable
Nutrition fry

The Bichir fry have external gills. Start feeding the fry after their entire yolk sac is eaten (1 week). Feed small live food, such as Artemia nauplii or microworms. Try to add the food near the fry, since newly hatched Bichir fry are not very active hunters.

Notes on reproduction

To ensure a high overall survival rate, the larger fry should be separated from the smaller fry, otherwise it will be eaten by older Bichirs.

Bibliography

Comment by the expert

Polypterus have several interesting adaptations. The swim bladder is divided into 2 parts, of which the right hand section is considerably larger. This functions as an accessory breathing organ and means the fish can survive out of water for some time, provided it is kept moist. Like Ananbantoid species, this fish may actually drown if it is denied access to atmospheric air.

Young bichirs have amphibian-like external gills which are lost as the fish matures. This, coupled with their nocturnal mode of hunting, in which they emerge from their daytime refuges to hunt invertebrates and small fish in shallow water, clearly exhibits the link these species form between fish and amphibians.