Bichirs (Polypterus bichir) are ancient-looking tropical freshwater fish that have captivated aquarium enthusiasts for years. Their unique appearance, reminiscent of a cross between a snake and an eel, combined with their relatively manageable care requirements, makes them a popular choice for those seeking an interesting and rewarding aquatic pet. Among the various types of bichirs, the dinosaur bichir (Polypterus senegalus), also known as the Senegal bichir, is one of the most commonly encountered in the aquarium trade. This article delves into the specifics of the dinosaur bichir's diet, providing a comprehensive guide to ensure the health and longevity of these fascinating creatures.
Understanding the Dinosaur Bichir
The dinosaur bichir is native to a wide range of freshwater habitats across Africa, including rivers, lakes, and floodplains like the Nile River, Lake Chad, and the Senegal River. They prefer shallow, swampy waters and can even thrive in semi-brackish conditions. These fish are well-adapted to varying water conditions and are often found in slow-moving waters with abundant vegetation and hiding spots.
These fish possess an elongated, eel-like body and a distinctive serrated dorsal fin reminiscent of dinosaurs. Despite their appearance, they are not true eels. Dinosaur bichirs are slow swimmers due to their small pectoral fins, which limits their predatory abilities. However, they possess a modified swim bladder, enabling them to breathe atmospheric oxygen, which allows them to survive in low-oxygen environments. Because of the murky waters where they come from these fish have very poor eyesight. Instead, bichirs use their other senses to navigate and find food. They have a good sense of smell and also are able to sense electricity in the water, thanks to ampullae of Lorenzini, little organs that can pick up the electricity of other animals in the water. Bichirs are an interesting fish because they have a pair of lungs and need access to the surface to get oxygen. One of the main reasons for this is the waters where they come from are usually so swampy and dirty that it makes breathing a challenge. Bichir lungs are a bit different than the lungs of other fish such as dwarf gourami. A bichirs lungs are more of a sac than a mass of tissue.
The average lifespan of a bichir is 10-15 years in captivity, a testament to their resilience when provided with proper care. The lifespan of these fish can be impacted significantly by the conditions they live in. The average bichir fish size is between 1-2.5 feet in length.
Dietary Needs of the Dinosaur Bichir
Since bichirs are carnivores you’ll need to ensure that they’re getting enough protein-rich food in their diet to stay healthy. The Senegal Bichir is carnivorous and should be provided with a protein-rich diet consisting of meaty foods. In terms of their actual diet, this is where bichir care can get a little trickier than other fish. You shouldn’t rely on pellets or flake food and instead need to give them a mix of protein-rich live, dry, and frozen foods. This might be a little more time consuming than you’re used to, but it’s what they need. They love live, frozen, and meaty foods like shrimp, worms, and fish fillets.
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A Varied Diet is Key
A varied diet is essential for the health and well-being of dinosaur bichirs. A mix of different food types ensures they receive all the necessary nutrients. Here's a breakdown of suitable food options:
Live Foods: Live foods can be an excellent way to stimulate a bichir's natural hunting instincts. Suitable options include:
- Bloodworms
- Blackworms
- Earthworms (from pesticide-free gardens)
- Prawns
- Small pieces of filleted fish
Frozen Foods: Frozen foods offer a convenient and nutritious alternative to live foods. Popular choices include:
- Bloodworms
- Krill
Dry Foods: High-quality carnivore pellets or sinking wafers can supplement the diet. Look for pellets with a high protein content and animal-based ingredients. Pellets can still be used to supplement their diet. Bichirs will often eat sticks or pellets such as shrimp, fish, seafood, worm, spirulina, brine shrimp or algae-based foods. The first 3 ingredients are animal or algae-based before moving to filler ingredients, eg Fish meal, shrimp meal and krill, “fillers and other ingredients”.
Meaty Foods: Offer them a variety of meaty foods, including occasional meals of beef heart.
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Feeding Frequency and Timing
Because of their nocturnal nature, you’ll want to time their feedings appropriately. Nighttime or early in the morning before their lights are off is a good choice. Trying to reprogram a fish away from their natural feeding behavior is an uphill battle. It is important not to overfeed your bichirs due to their ability to pack on food. In a captive environment, they do not exert as much energy as a wild fish would, therefore making them susceptible to obesity and fatty liver disease, a common cause of death for many captive fish. Avoid overfeeding, as these fish can become overweight if fed too frequently.
Important Considerations
- Thiaminase: Some foods, like market shrimp, contain thiaminase, an enzyme that breaks down vitamin B1 (thiamin). Thiamin deficiency can lead to nervous system problems. If feeding raw seafood, pre-soak it in a vitamin product containing vitamin B1. Minimise the use of crustaceans, and never, ever feed cyprinids (Minnows) as they contain thiamine deficiency, and to a degree can also be used to treat it.
- "Feeder" Fish: While offering live fish might seem like a natural choice, it's crucial to exercise caution. Any feeder fish should ideally be bred at home or quarantined for extended periods due to the sub-standard conditions in which they are raised, and the high rates of disease and parasites.
- Tank Mates: Although this species is generally peaceful, it is a predator by nature and will eat any tank mates small enough to fit in its mouth. When selecting tank mates, avoid small fish like tetras or guppies. Instead, pair them with larger, similarly peaceful species that occupy different levels of the tank, such as larger cichlids or catfish. You’ll also want to make sure that their tank mates allow enough food to reach the bottom of the tank.
Addressing Feeding Problems
It's not uncommon for bichirs to occasionally go on "hunger strikes." Here's how to address potential feeding issues:
- Monitor Water Quality: Ensure stable, high-quality water conditions.
- Offer Variety: Try different food options to pique their interest.
- Observe Behavior: Watch for signs of illness or stress. A small dark spot on top of head, might even be a hole.
- Quarantine: If a bichir is refusing food and exhibiting abnormal behavior, isolate it in a separate tank for observation and treatment.
Creating the Ideal Habitat
Setting up an aquarium for the Senegal Bichir (Polypterus senegalus), the key is to provide a tank with a large footprint rather than a deep one, as these fish are bottom-dwellers and don’t require much vertical space. A tank of at least 120 cm (48 inches) in length is recommended, allowing them ample room to explore. Low, flat tanks are ideal, but remember that Senegal Bichirs are excellent jumpers, so it’s crucial to use a tightly fitting lid to prevent escapes. The minimum recommended tank size for these fish is around 90 gallons for one.
The one thing you’ll want to remember when setting up their tank is to get the right substrate. We highly recommend a sandy substrate for bichir. Gravel substrate can be too rough on their bellies and there have even been reports of bichir accidentally eating it when scavenging for food.
Maintaining a Healthy Environment
Key to their longevity is maintaining stable, high-quality water conditions, providing a nutritious diet, and ensuring that they are housed in a stress-free environment. Even though bichir can get their oxygen from the surface you should always perform regular water changes and monitor the levels in your aquarium with a test kit.
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Breeding Dinosaur Bichirs
Breeding Polypterus senegalus in captivity is rare but not impossible. This species is an egg scatterer, meaning the female will lay hundreds of eggs, which are then fertilized and scattered throughout the tank by the male. To encourage breeding, replicate their natural environment by adding dense planting and slightly lowering the water temperature. The male collects the eggs using his anal and caudal fins, fertilizes them, and scatters them around the tank, particularly in the plants. Once the eggs hatch, which typically takes 3-4 days, the fry remain inactive for several more days before becoming free-swimming. At this stage, they can be fed newly hatched brine shrimp or other suitable fry food.