Have you always dreamed of having your own pet dinosaur? With a polypterus, you can! This ancient fish first appeared during the Cretaceous period over 60 million years ago, alongside pterosaurs, ichthyosaurs and plesiosaurs. Modern day polypteridae include erpetoichthys calabaricus, also known as the reed fish or rope fish, and the dozen or so members of the family erpetoichthys polypterus commonly known as bichirs.
Polypterus can be identified by its long, snake-like body and the multiple dorsal finlets along its spine that inspired its name (polypterus means “many fins”). Its large pectoral fins give it a distinctive way of swimming. Tough ganoid scales protect it from infection and parasites. It is not difficult to meet a polypterus’ needs, and it is a popular choice for the home aquarium.
When setting up a tank for your polypterus, keep in mind that even smaller varieties can grow to be over a foot long. Some species, including the red bichir and the fat-headed bichir, can be two feet long, and the mammoth Congo bichir can grow to over three feet. A 48 x 15-inch tank is sufficient for smaller fish. For larger varieties, a 6 x 2-foot tank is more appropriate.
Polypterus are bottom dwellers, so ample floor space is essential. Choose a shallow tank with a large footprint so your fish can roam the bottom but still reach the top easily. These fish have a modified swim bladder that enables them to supplement their oxygen with gulps of air from the surface, so make sure to leave an air gap between the water and the cover of your tank. Secure the tank cover well, as these fish are master escape artists.
These fish are hardy and can tolerate variation in the quality and temperature of their water, but they will be most comfortable in soft to slightly hard water that is neutral or slightly acidic and kept at a temperature between 25 and 28 °C (77-82 °F).
Choose a substrate that is easy to keep clean, such as soft aquarium sand or horticultural silver sand. Arrange smooth rocks and large pieces of wood to create caves for your fish to slink in and out of. If you plan to have more than one bichir, prevent them from becoming territorial by providing a hiding place for each one. Use robust plants to provide cover, as this species’ poor eyesight makes it clumsy and prone to damaging more delicate varieties.
Diet and Nutrition
Because of its poor eyesight, the polypterus relies on its sense of smell to seek out its food. This carnivore enjoys many foods, including:
- Meaty foods, including mussel, prawn, shrimp, cockle, whitebait, beefheart and silversides
- Live foods, including guppies, minnows, earthworms and ghost shrimp
- Frozen foods, including bloodworms, brine shrimp, Mysis shrimp, squid, krill and silversides
- Sinking catfish pellets
- Algae wafers
- Sinking granular foods
Polypterus are not aggressive but will eat smaller fish if given the opportunity. They may also snap at one another, particularly when fighting over food, but typically do not cause any real harm. They should be tanked with non-aggressive fish of a similar size, such as Siamese tigerfish, knifefish, tinfoils and medium-sized catfish.
Polypterus are a fascinating fish that provide a window into a long-ago time. Find everything you need to add this ancient creature to your tank at Big Al’s.