fish difficult level

Polypterus cf. senegalus

Bichir

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Submitted by
Natasha Khardina

Water Chemistry

Water information

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

Chemical parameters

pH
6.0-8.0
Conductivity
GH
5-19 mg/l
KH
Dissolved Oxygen

Biology

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

In Nature Polypterus senegalus prefers shallow, slow moving waters of swamps, marshes and freshwater lagoons, where it can find enough food and reproduce.

If biotope correct, this species should be kept in the aquarium only with larger fish, which it can’t eat. Otherwise, mono-species tank is the best option.

Aggression grade
Predator
Activity
Night active
Sexual dimorphism

Polypterus senegalus becomes mature already in the size of 15 – 23cm, although male bichir also tend to be smaller than female bichir.

Main difference between male and female is that the anal fin of the male is thicker. During the spawning a male uses this enlarged, swollen, and folded in a cup-like fashion anal fin to brush the female.

Nutrition in Nature

In its natural biotope Polypterus senegalus feeds on fishes, frogs, insects, crustaceans and mollusks. While its subspesies Polypterus senegalus senegalus is mainly insectivorous.

Reproduction

Breeding tank set-up

To be able to breed Polypterus senegalus need an environment, which is perfect for them – good water quality (slightly acidic and soft water), frequent water changes, right size aquarium. Water changes and temperature fluctuations are key factors to induce spawning.

A varied diet with plenty of live meat foods is recommended.

Nutrition parents

In the captivity Polypterus prefers meaty foods rarely accepting dry food.

Mating type
Monogamous
Spawning behaviour

The female needs a suitable spawning site before laying eggs – she will prefere a densely planted site with shrubs and mosses.

The spawning ritual usually lasts 1 day: male bichir chases the female and also bump into her with his muzzle.

The female of Polypterus senegalus lays from 100 to 300 eggs in a few days. She lays several eggs each time, and the eggs are fertilized by the male when he hugs his anal and caudal fins around the female’s genital area.

The male takes the eggs, fertilizes them, and then they are scattered over the plants. The bichir egg is 2-3 millimeters thick and slightly sticky. They will stick to the plants until the fry hatch after three to four days.

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

Bichir fry have external gills. Before starting feeding the fry wait about a week, as they must first consume the entire yolk sac. The first food should be small live food such as freshly hatched brine shrimp (Artemia nauplii) or microworms.

When feeding, put food next to the fry, as newly hatched bichir fry are not very active hunters. Since the older bichir fry are prone to cannibalism, it is necessary to remove the larger fry from the smaller ones to assure higher survival rate.

Notes on reproduction

Bichirs sometimes feed on their own eggs, so it may be a good idea to remove the parents from the tank as soon as final fertilization is over.