Common Name: Zaire Green Bichir
Scientific Name: Polypterus retropinnis
The Zaire Green Bichir is a wild-caught bichir from Central Africa that is less commonly seen in the hobby. It has the elongated, armored body and row of small dorsal finlets typical of bichirs, and as its trade name suggests, it tends toward greenish tones.
Habitat and Distribution:
Polypterus retropinnis is native to the Congo basin of Central Africa, where bichirs live in slow-moving rivers, floodplains and swampy, heavily vegetated margins. These warm, often oxygen-poor waters are a good match for the bichir’s ability to breathe air.
Size and Lifespan:
This species reaches about 12-14 inches (30-35 cm) as an adult. Like other bichirs it is long-lived, and 10-15 years is typical for the genus with good care.
Diet and Behavior:
Like other bichirs, it is carnivorous and feeds on insects, worms, crustaceans and small fish in the wild. In the aquarium, offer sinking carnivore pellets, frozen bloodworms, krill and shrimp. It is mainly active at dusk and at night and will eat any tank mate small enough to swallow. Wild-caught fish may take a little time and some frozen foods before accepting pellets.
Breeding and Reproduction:
Breeding Polypterus retropinnis in aquariums is rarely reported. Like other bichirs, it is an egg scatterer: the male cups his anal fin to fertilize the eggs, which are scattered among plants and left without parental care.
Aquarium Care and Tank Requirements:
A tank of at least 125 gallons is recommended for an adult. The tank should have plenty of floor space, a soft sand or smooth gravel substrate, and driftwood or caves for cover. Bichirs are expert escape artists that can squeeze through surprisingly small gaps, so a tight-fitting lid with all openings covered is essential. Leave a little air space at the surface so they can breathe. The water temperature should be kept between 75-82°F (24-28°C), with a pH of 6.5-7.5 and soft to moderately hard water.
Ideal Tank Mates:
Bichirs do well with fish that are too large to fit in their mouths, such as medium to large cichlids, larger barbs, arowanas, knifefish, synodontis catfish and other bichirs. Avoid small tetras, livebearers and shrimp, which will be eaten at night, and very aggressive fish that may nip at them.
Difficulty Level:
Intermediate. This bichir is hardy once settled, but wild-caught fish need time to acclimate and a large, well-covered tank as they grow.
Water Parameters:
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Temperature: 75-82°F (24-28°C)
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pH: 6.5-7.5
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General Hardness (GH): 3-12 dGH
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Carbonate Hardness (KH): 2-8 dKH
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Ammonia: 0 ppm
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Nitrite: 0 ppm
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Nitrate: <20 ppm (regular water changes required)
Additional Information:
- Bichirs have a pair of primitive lungs and regularly swim to the surface to gulp air, which is completely normal behavior.
- They have poor eyesight and find food mainly by smell, so sinking foods offered in the evening are often taken most readily.
- Fun fact: Bichirs belong to an ancient lineage of ray-finned fish with a fossil record stretching back tens of millions of years, which is why they are often called living fossils.
The Zaire Green Bichir is a rewarding addition for keepers who enjoy these ancient, air-breathing fish.
