Bichir

Bichirs and the reedfish belong to the family Polypteridae, which is the only family in the order Polypteriformes. These fish are special because they are very old types of ray-finned fishes and have been around for millions of years.

All bichir species live in freshwater habitats in tropical Africa and the Nile River system, especially in swampy, shallow floodplains and estuaries. They are often found in slow-moving or still waters where they can hide among plants.

Bichirs are sometimes called "living fossils" because they have changed very little since they first appeared millions of years ago. They are closely related to other ray-finned fishes, but they also have unique features that make them interesting to scientists and fish lovers.

Anatomy

Bichirs, also called polypterids, are special fish with long, slender bodies. Instead of one dorsal fin, they have a row of small finlets with stiff, double-edged tips. Their other fins are soft. Their bodies are covered in thick, bony scales called ganoid scales.

Bichirs have some unique features. They have fleshy pectoral fins like lobe-finned fishes. They also have small openings on top of their heads called spiracles that help them breathe air. They have two lungs for breathing, with the larger right lung stretching along their body. Bichirs can grow from about 25 cm to over 100 cm long, depending on the species.

Main article: dorsal fin

ganoid

jaw

tetrapods

teleost

lobe-finned fishes

spiracles

lungs

oesophagus

Diet and traits

Bichirs, also called polypterids, are night-time fish that look for small animals to eat. They eat tiny vertebrates, crustaceans, and insects. In aquariums, they are often given bloodworms to eat. These fish have a great sense of smell to help them find food. When it's time for babies, a female bichir lays eggs, and the male helps them grow.

Air breathing

Bichirs, also known as polypterids, have special paired lungs connected to their throats by a glottis. This helps them breathe air from the surface when the water doesn’t have enough oxygen. Their lungs pull in air and send oxygen-rich blood to their bodies. Unlike many other fish or land animals, their lungs are smooth sacs without tiny air pockets. Bichirs use a special way of breathing called "recoil aspiration." They often use tiny openings on the top of their heads, called spiracles, to breathe when resting or in very shallow water.

Polypterids as aquarium specimens

Polypterids, also called dragon bichir or dragon fin, are popular in large public and hobby aquaria. They are peaceful fish that usually rest on the tank bottom but will swim around if there are many large plants. They can live for many years, from 10 to over 30 years, in captivity. These fish do well in tanks with lots of plants, which look like their natural home in Africa. They can be kept with other large fish that are not too big to eat them and not too small to be eaten by them.

Classification

Bichirs are a special group of ancient ray-finned fish called Polypteridae. They live in freshwater in tropical Africa and the Nile River, especially in swampy areas. There are two main living types of bichirs: Polypterus and Erpetoichthys. Together with some extinct types, they make up the order Polypteriformes. These fish are unique because they are closely related to all other living ray-finned fish.

The living species include the reedfish (Erpetoichthys calabaricus) and several species of bichir under the genus Polypterus. Some well-known types are the Nile bichir, the ornate bichir, and the gray bichir, each with their own special looks and habitats.