The Senegal Bichir, scientifically known as Polypterus senegalus, is a fascinating freshwater fish native to West Africa. Often called the "dinosaur eel" due to its ancient appearance and elongated body, it's a popular choice among aquarium enthusiasts who appreciate unique and hardy species.
Physical Characteristics:
- They have an elongated, cylindrical body covered in hard, rhomboid-shaped scales that act like armor.
- A distinctive serrated dorsal fin runs along most of their back, consisting of 8-11 individual finlets.
- Their pectoral fins are large and paddle-like, which they primarily use for slow, graceful movement and "walking" along the substrate.
- They possess a pair of primitive lungs in addition to gills, allowing them to breathe atmospheric oxygen. You might see them occasionally dart to the surface to take a gulp of air.
- Senegal Bichirs typically have a grey or beige base color, sometimes with shades of white, pink, or bluish. Albino variations also exist.
- They have poor eyesight and rely heavily on their sense of smell and the ability to detect subtle movements to find prey.
- Their mouth is large with a row of slightly curved teeth in both the upper and lower jaws.
- Sexual dimorphism is present; males are generally smaller and have a thicker anal fin than females.
Size:
- In the wild, they can reach up to 70 cm (28 inches), although most commonly grow to around 48 cm (19 inches) in captivity. Some sources suggest they rarely exceed 30-35 cm (12-14 inches) in home aquariums, possibly due to captive breeding.
Distribution and Habitat:
- Senegal Bichirs are widely distributed across tropical Africa, including the Nile River system and at least 26 countries such as Senegal, Egypt, Nigeria, and Kenya.
- They inhabit shallow, slow-moving waters like swamps, marshes, lakes, estuaries, and small tributaries, often with dense vegetation.
Behaviour and Compatibility:
- They are primarily nocturnal predators, spending the day hiding and emerging at night to hunt.
- While generally peaceful with fish too large to eat, they are semi-aggressive and will readily consume any tank mates small enough to fit in their mouths.
- They are bottom dwellers and spend most of their time exploring the lower levels of the aquarium.
- Senegal Bichirs are excellent escape artists, so a tight-fitting lid on the aquarium is essential.
- Suitable tank mates include other larger, non-aggressive fish such as other Bichir species, larger South American and African Cichlids, Knifefish, Datnoids, and larger Ctenopoma species. Avoid keeping them with small fish or aggressive tank mates. Common plecos and other algae eaters that might suck on their slime coat should also be avoided.
Aquarium Care:
- Tank Size: A tank with a large footprint is more important than height. A minimum of 150x60x60 cm (around 90 gallons or larger) is recommended for an adult.
- Substrate: A soft, sandy substrate is ideal to prevent damage to their delicate underbelly. Avoid gravel or small stones that could be ingested.
- Décor: Provide plenty of hiding places using driftwood, smooth rocks, and plants. While plants aren't essential, they offer shade and security.
- Water Parameters:
- Temperature: 24-28°C (75-82°F)
- pH: 6.0-7.8 (adaptable to a wider range but stable conditions are key)
- Hardness: 5-20 dH
- Filtration and Water Changes: Maintain high water quality with adequate filtration and regular water changes (10-25% every 2-4 weeks).
- Lighting: They prefer dim lighting as they are nocturnal.
- Tank Lid: A tight-fitting lid with a small gap above the waterline is crucial to prevent escapes while allowing them to breathe air.
Feeding:
- Senegal Bichirs are carnivorous.
- Offer a varied diet of meaty foods such as high-quality pellets, frozen bloodworms, brine shrimp, mysis shrimp, pieces of white fish, and prawn. Live foods can stimulate their predatory instincts but should be from a safe source.
- Feed them small amounts 2-3 times daily, preferably at night when they are most active. Avoid overfeeding.
Breeding:
- Breeding Senegal Bichirs in captivity is extremely difficult and rarely achieved by hobbyists.
- In nature, they breed during the rainy season. Courtship involves the male chasing and nudging the female. The female lays 100-300 eggs, which the male fertilizes by cupping his anal and caudal fins around her. The eggs are then scattered among vegetation.
- If spawning occurs, the adults should be removed as they may eat the eggs. The eggs hatch in 3-4 days, and the fry become free-swimming about 3 days later, requiring small live foods like brine shrimp nauplii.
Other Interesting Facts:
- Senegal Bichirs are considered living fossils, with relatives dating back to the Triassic period (over 200 million years ago).
- Their divided swim bladder acts as an accessory breathing organ, allowing them to survive out of water for short periods if kept moist. However, they can drown if denied access to atmospheric air.
- Juveniles possess amphibian-like external gills that disappear as they mature.
- Their tough skin has been studied as a model for personal armor due to its combination of protection and flexibility.
Keeping a Senegal Bichir can be a rewarding experience for the experienced aquarist who can provide the appropriate environment and diet for this unique and ancient fish.
