Sometimes called dinosaur eels, Bichirs (Polypteridae) are true living fossils that split from other ray-finned fish 400 million years ago. They have gills but also need to breathe air, like the first animals to walk on land. Bichir fish are carnivorous and grow 1 to 3 feet long. They are not difficult to care for, however, and have a lifespan that lasts decades.
What are Dinosaur Bichir Eels?
How to pronounce their name is somewhat of a challenge because the word is French in origin. And the French word “Bichir” was meant to be a phonetic take of the Egyptian name. So “Bichir” has no true English equivalent. Using the International Phonetic Alphabet we get /ˈbɪʃɪər/, if that helps.
The bichir family is related to the one that gave rise to the first amphibians. They have a tendency to “walk” on the aquarium bottom with their well-developed pectoral fins. It’s just one of their adaptations that led to their descendents shifting to land life.
One lesser known fact about Bichirs is that unlike most fish they breathe air. They are facultative air-breathers, meaning when oxygen levels get low in their environment they take gulps of atmospheric air.
Bichirs have true lungs as well as gills for water breathing. Both organs enable them to survive when water levels are low and oxygen-poor during the drought season. In most fish tanks water is well oxygenated so they don’t bother breathing air.
Despite being exotic and ancient, Bichirs are easy to find in the aquarium hobby. They cost between $20 and $150, depending on the size and species. The Senegal or Gray Bichir (Polypterus senegalus) is one of the most popular, and also one of the smallest. The desirable Ornate Bichir (Polypterus ornatipinnis) grows twice as long and costs more.
- Scientific Name: Polypteridae family
- Origin: Africa
- Length: 12-36 inches
- Aquarium Size: 55-250 gallons
- Lifespan: 15-20 years
- Ease of Care: Easy
- Temperament: Peaceful; Predatory
Bichir Care Guide
Here are a few things you should consider when it comes to Bichir care:
Bichir Tank Size
Bichirs vary a lot in size so it’s not possible to say with precision how large of an aquarium you need. Even a full grown Dinosaur Bichir will be a foot long. Bichir fish aren’t active fish and tend to crawl along the bottom. So a 55 gallon aquarium is the bare minimum for an adult Senegal or Delhezi Bichir.
A 75 gallon is a bit more comfortable thanks to the extra 6 inches of width. An Ornate Bichir or other large species is going to need at least 180 gallons of space or more.
Bichirs aren’t fast growing fish, though. Your bichir will grow about 2-3cm per month and slow down as they reach their final adult size. It may be a few years before your baby Ornate Bichir becomes a tank-buster.
A spacious tank is also important because these massive fish are thick and muscular. They move about slowly but a hunting or frightened adult Bichir could launch itself out of a too-small aquarium.
Bichir Aquarium Water Conditions
Considering their ability to thrive in drought conditions it should come as no surprise that Bichirs are not very picky about water conditions.
They thrive in moderate acid and alkaline conditions (pH 6.5-7.5. As well as moderate hardness between 4 and 8 dGH. Water temperature should be on the warmer side (78-82F) year-round. Cool spells are associated with breeding conditions (see below).
Filtration is a major issue because Bichirs are large predators who create large amounts of waste. Extended ammonia and nitrite exposure is never healthy for fish and will lead to suppressed immunity and eventual death.
Plants and Decorations
Unlike many other large fish Bichirs are easy on plants, substrates, and decorations. They don’t dig into gravel, uproot plants, or move caves about. So long as they have ample retreat zones like driftwood crevices or clay pottery to hide within they are more likely to stay out in the open.
Heavy planting replicates their natural habitat and also lock away phosphates, nitrates, and other algae-growing nutrients. Most aquarists don’t use high-intensity plant lights on a Bichir tank. Look instead to Java Fern, Java Moss, Anubias, and other low-light plants that will still create plenty of shade and cover for your fish.
Bichir Tank Mates
Bichir owners have little to worry about when it comes to tank mates. As long as your Bichir cannot swallow it you’re in good shape. Many guides list bichirs as “aggressive” but that’s not accurate. They are predatory but won’t bother tank mates that are too large to eat.
Bichir fish are tolerant of a wide range of water conditions. They can be kept in both soft and hard water aquariums alongside all kinds of medium to large community fish.
I recommend staying away from slow-moving fish with long fins, such as fancy Goldfish. While Bichirs won’t be able to eat an adult Oranda or Comet their trailing fins are tempting targets to nip at. Torn fins cause stress and open a route for disease to take hold.
Good Tank mates for Bichirs
- Cichlids
- Large Characins (Silver Dollars, Piranha, etc)
- Medium to large Barbs
- Large Rainbowfish
- Gouramis
- Other Bichirs
You should avoid fish that are either small enough to be eaten or are aggressive. Cichlids are good tank mates most of the time. But when cichlids start spawning they will harass the slow moving Bichir. Small, thin fish like Livebearers and Tetras will be eaten by even the smallest Bichirs. The same goes for small shrimp and other invertebrates.
Poor Tank Mates for Bichirs
- Spawning Cichlids
- Bettas
- Shrimp
- Livebearers
- Tetras
What Do Bichir Fish Eat?
Bichirs are carnivorous and will eat anything they are able to overpower and swallow. In the wild this includes worms, tadpoles, insects and smaller fish. Any of these are perfect for feeding aquarium specimens as well.
When young, offer your Bichir a mixture of live, frozen, and prepared foods. Notice the fan-like projections around their nostrils. Bichirs hunt by smell as much as by sight, often at night or in muddy water.
Bichirs also have Ampullae of Lorenzini, electrosensitive pores similar to those of sharks and other primitive fish. Using these Bichirs sense the electrical fields other animals give off through muscle contraction, even if buried or in total darkness. Combined with their strong sense of smell they root out prey no matter how well its hidden.
Since smell is more important than sight they will take thawed bloodworms, brine shrimp, chopped shellfish, and other somewhat smelly frozen food.
Sinking carnivore pellets have a rich scent and are accepted with little fuss. A bland formula might be enriched using a garlic flavored vitamin food soak. A Bichir trained on live food may need some convincing with feeding tongs before it learns to accept prepared items.
Live food should still be offered on occasion. Both quality and variety matter. Try offering live crickets, feeder goldfish, or nightcrawlers to see which gets the best response. Bichirs prefer to feed at night but are easy to train so they feed during the day.
Breeding Bichirs
Bichirs aren’t often bred in aquaria. They are too large and difficult to sex. But as they become more popular, more aquarists are having luck with spawning.
Bichir Fish Male vs Female
Like many fish the differences between males and females aren’t obvious to us humans. Besides scent and other subtle cues, many fish tell sexes apart by behavior rather than sight alone.
There are a few ways to sex adult Bichirs, however. Male fish reach sexual maturity by age 3, while females take 5 to 6 years to reach breeding age. Females younger than this may carry undeveloped eggs. But they may not be fully mature, which may cause the males to turn aggressive.
Males have a wider anal fin and often have a pointed tail fin. Females have a narrower anal fin and don’t have a point to the tail fin. Dinosaur eel full grown females are also larger and thicker than males in most species.
Conditioning Bichirs for Spawning
Bichirs aren’t bred often in captivity except in large outdoor ponds in tropical parts of the world. They are hard to breed in fish tanks because they prefer seasonal changes in climate, including cool spells. Bichir fish also look for weedy marsh plants to deposit their eggs in. Since so many are wild-caught they fail to reproduce without these spawning signals.
The best ways to encourage your adult Bichirs to reproduce are:
- Offer a diverse diet: Condition your Bichirs to begin producing gametes (eggs and sperm) by cutting out prepared foods. Switch to offering high quality live and frozen food.
- Lower the temperature to 72-74F: A temperature drop combined with a heavy water change signals seasonal changes that include spawning.
- Provide thick plant material for spawning: Bichers prefer thick plant beds to scatter their eggs within after fertilization. Java Moss and Guppy Grass are easy to find, grow, and perfect for sheltering the young fry.
Once the pair decide to spawn the female will release around 100-300 eggs in small batches at a time. The male collects each batch using his anal fin. It’s wide, distinctive shape acts like a scoop to hold the eggs while he fertilizes them. Once fertilized the male then scatters them among tangled plant material where the adhesive 2-3mm eggs attach.
Like amphibian fry, baby Bichirs have external gills that are eventually taken in as they mature. Give them a week to absorb their yolk sack before providing small sized live food like brine shrimp nauplii.
Conclusion
Dinosaur bichir fish are impressive predators that are easy to keep if you have the space for one. They are peaceful towards fish they can’t eat. And even though they are bottom dwellers they won’t rearrange the substrate or decorations.
FAQs
Do Bichirs Bite?
Dinosaur eel fish have a row of large and strong teeth they use for holding onto slippery prey like fish and tadpoles. They have a strong bite but don’t use their teeth for defense. A bichir would bite you only if it thought it was being fed. A large bichir might be able to break the skin, however.
Are Bichirs Hard to Keep?
The hardest part to caring for a bircher fish is the tank size. They are otherwise easy fish to care for. Even the smallest of them need at least 55 gallons of space. 125 to 180 gallons is the minimum for the species that grow 2 to 3 feet long. They also produce a lot of ammonia so you’ll need a powerful canister filter.
Can Bichir Walk Land?
Bichir fish are able to use their powerful pectoral fins to propel them across muddy land. They are able to breathe air as long as they stay moist. So they do “walk” on land but not very fast. Bichirs do this to find new places to live when seasonal bodies of water start to dry out.
