Bichirs: A Fish Out of Water Story

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It’s no secret to aquarists that life on earth began in the water. Over a period of billions of years, life found its way to terrestrial habitats. A few “linking” species have survived their ancient ancestors to live in fringe habitats between water and land. Bichir fish are some of the last surviving descendants of fish whose fossils archaeologists uncovered side by side with dinosaur bones. As some of the first swimmers to venture into terrestrial habitats, they exhibit some unique characteristics including a specialized swim bladder that functions as lungs with very efficient gas exchange. This gives them the curious ability to survive outside water for extended periods, and they may actually drown if they do not have access to atmospheric oxygen.

These prehistoric swimmers are characterized by their elongated eel-like bodies with repeating mohawk-like ray-fins down their spines. All species of bichirs in the genus Polypterus are nocturnal, spending their days hiding out, and emerging only after dark to hunt small fish, crustaceans and other invertebrates in shallow water. They have become extremely popular in the freshwater aquarium trade for their interesting physical appearances, and their serene dispositions. While they are predatory, bichirs can be quite peaceful and great for community-living so long as their tankmates are not bite-sized. The Wet Spot is proud to host a large assortment of bichirs, and while we’d love to discuss them all, a few of our favorites are Polypterus cf. lapradei, Polypterus teugelsi, and Polypterus palmas palmas.

Spending its days hiding out in caves or under driftwood of the shallow lakes, rivers and marshes of East Africa, P. cf. lapradei waits out the sun before slithering along the sandy shores to hunt. Also known as the Striped Bichir, this eel-like specimen reaches up to 29 inches in the wild and is feared large and wide by small vertebrates and invertebrates alike. In captivity, striped bichirs are likely to grow to 18 inches in length, and require tanks with large bases and plenty of floor space with sandy substrate, and a scattering of rocks, caves, and driftwood to provide hiding places during the day. As voracious carnivores, bichirs should be fed regular meals of live and frozen fare including prawns, bloodworm, mussels, snails and other similar fare. Some specimens will, however, accept high quality sinking pellets in a pinch. They thrive in shallow waters, though much to the chagrin of dedicated aquarists, these bichirs are likely to Houdini their ways out of tanks that do not have tight fitting lids. Waters should be maintained with temperatures between 72 and 82°F, pH of 6.0 to 8.0, and hardness between 5 and 25°H.

Slightly less intimidating than our last bichir, P. teugelsi reaches a mere 16 inches in length, and sports a beautiful set of feathered tail fins that remind evolutionary biologists everywhere that dinosaurs and birds share recent ancestry. Their long bodies are a beautiful copper color with dark spots, and a pale underbelly. Native to the river cross drainage of Cameroon, “Teugels’ Bichirs” require the same tank set ups and diet as striped bichirs. Bichirs are not to be trusted in community tanks with species that fit in their mouths, though they have been reported to live peacefully with knife fish, butterfly fish, and other bichirs. Waters should be maintained with temperatures between 72 and 82°F, pH of 7.0 to 7.5, and hardness between 1 and 5°H.

Found in the same habitats and regions as the Striped Bichir, P. palmas palmas is our smallest bichir of the day. More commonly known as the “Marbled Bichir”, this species is slightly less daunting for the snake-fearing aquarists among us. This bichir exhibits a beautiful dark marbled pattern over tan and green bodies, red eyes, and a set of sensitive barbels near their mouths used to sniff out their prey. Follow general bichir tank setup requirements outlined above, though reports indicate this species appreciates some greenery to provide additional cover. Waters should be maintained with temperatures between 72 and 82°F, pH of 6.0 to 7.0, and hardness between 5 and 15°H.

All bichirs are amazing oddball fish to behold on the day to day, providing unsolicited natural history lessons to their observers. Practically speaking, these fun species are incredibly hardy and easy to care for.