Nile Bichir is an ancient nocturnal predator with primitive lungs, requiring a spacious aquarium of at least 400 liters and a tightly sealed lid.
Overview
Polypterus bichir, commonly known as the Nile Bichir, is one of the most impressive members of the Polypteridae family. These fish are true "living fossils" -- their ancestors existed over 60 million years ago, and they have remained virtually unchanged since then. In the wild, Polypterus bichir inhabits freshwater bodies across Africa, including the Nile basin, Lakes Chad and Turkana, and flooded river plains.
The body is elongated and snake-like, covered with tough ganoid scales that serve as reliable armor. The dorsal fin is divided into numerous separate finlets -- a characteristic feature of all polypterids. Adults reach impressive sizes of 60 to 75 cm. With proper care, their lifespan ranges from 15 to 20 years.
A key biological feature of Polypterus bichir is the presence of primitive lungs that allow it to breathe atmospheric air. The fish periodically rises to the surface to gulp air, and this is vital for its survival. The Nile Bichir is nocturnal by nature: it prefers to hide among shelters during the day and emerges to hunt after dark.
Tank Requirements
Given the impressive size of adult Polypterus bichir, the minimum tank volume should be at least 400 liters. The bottom footprint matters more than water column height, as polypterids are bottom-dwelling fish. An elongated rectangular tank is the optimal choice.
Water parameters should be maintained within the following ranges: temperature 24-28 °C, pH 6.5-7.5, and general hardness GH 5-20. Polypterids are fairly hardy regarding water chemistry, but sudden fluctuations must be avoided.
Use fine sand or rounded gravel as substrate -- sharp substrates can injure the fish's delicate belly. The setup should include driftwood, large rocks, and ceramic tubes to create hiding spots. Live plants are possible, but be prepared for a large fish to uproot them -- hardy broad-leaved species attached to decorations are preferable.
A tight-fitting lid is absolutely essential! This is a critical point: polypterids are notorious escape artists. They can crawl through the smallest gaps using their powerful pectoral fins. All equipment openings must be securely sealed. Leave an air gap of 3-5 cm between the water surface and the lid so the fish can freely breathe atmospheric air.
Lighting should be subdued, matching the species' nocturnal lifestyle. Floating plants are recommended to create shaded areas.
Feeding and Diet
Polypterus bichir is a dedicated predator. In the wild, it feeds on small fish, frogs, crustaceans, and aquatic insects. In aquarium conditions, the core diet should consist of:
- live and frozen foods: bloodworms, shrimp, small fish, pieces of tilapia or pollock fillet;
- specialized sinking pellets for carnivorous fish (once the fish has acclimated);
- mussel and squid meat as supplements.
Feeding should take place in the evening or at night when the bichir is most active. Food must sink -- polypterids feed at the bottom and rarely take food from the surface. Juveniles should be fed daily, while adults need feeding only 3-4 times per week. Overfeeding is dangerous: polypterids are prone to obesity when given excessive food.
Care and Maintenance
Despite a moderate care level, Polypterus bichir requires an attentive approach. Weekly water changes of 20-30% are essential to maintain water quality. Use a reliable filtration system with good mechanical and biological capacity -- a large predatory fish generates a significant bioload.
It is crucial to provide the fish with unobstructed access to the water surface. The primitive lungs of Polypterus bichir are not optional -- the fish will die if it cannot breathe atmospheric air. Ensure that floating plants or decorations do not block the path to the surface.
Test water parameters regularly. Polypterids are sensitive to elevated ammonia and nitrite levels. Check the condition of the lid and all equipment openings routinely -- an escape from the tank usually results in the fish's death.
When keeping multiple polypterids together, ensure each individual has sufficient hiding spots. Polypterids are territorial, and a shortage of shelters may lead to conflicts.
Compatibility
Polypterus bichir is a semi-aggressive species, and choosing tank mates requires careful consideration. The main rule is simple: any fish that fits in the bichir's mouth will be eaten. Therefore, companions must be of comparable size.
Good tank mates include:
- other polypterid species, such as Barred Bichir or Endlicheri Bichir;
- large synodontis catfish and other catfish of comparable size;
- large cichlids with a moderate temperament;
- large characins and cyprinids.
Avoid keeping bichirs with small fish (neons, guppies, small tetras), overly aggressive cichlids, or fin-nipping species. Despite their tough scales, polypterid fins are relatively delicate and vulnerable to damage.
Breeding
Breeding Polypterus bichir in an aquarium is a challenging endeavor that few aquarists accomplish successfully. In the wild, spawning coincides with the rainy season, when water levels rise and abundant vegetation becomes available.
To stimulate spawning in an aquarium, the following approach is recommended:
- gradually lower the temperature by 2-3 degrees, then slowly raise it to 27-28 °C to simulate seasonal changes;
- increase the proportion of live food in the diet for 2-3 weeks before the expected spawn;
- provide an abundance of fine-leaved plants or synthetic spawning substrates;
- maintain impeccable water quality.
Sexual dimorphism is subtle: males typically have a broader, fleshier anal fin. During spawning, the male forms a cup-like shape with his anal fin to receive eggs. The female scatters eggs among the vegetation, after which the parents should be removed, as they may consume the eggs.
Incubation lasts 3-4 days. The larvae initially feed on their yolk sacs, then should be transitioned to infusoria and newly hatched brine shrimp. Fry grow slowly and require meticulous care. Raising juvenile polypterids is a process that demands patience and experience.