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 among the oldest 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 easily 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 set them apart, making them fascinating to scientists and fish lovers alike.

Anatomy

Polypterids, also known as bichirs, are special fish with a long, slender body and a row of dorsal finlets instead of one single dorsal fin. These finlets have double-edged tips and are the only fins with stiff spines; the other fins are soft. Their bodies are covered in thick, bony scales called ganoid scales.

Bichirs have some interesting features that set them apart from other fish. They have fleshy pectoral fins like lobe-finned fishes and small openings on top of their heads called spiracles that help them breathe air. They also have two lungs for breathing, with the larger right lung stretching the length of their body cavity. These fish can grow anywhere 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 known as polypterids, are nocturnal fish that hunt for small animals like tiny vertebrates, crustaceans, and insects. In aquariums, they are often fed bloodworms, which are a special kind of larva. These fish have an amazing sense of smell, which helps them find their food. When it's time to have babies, a female bichir lays between 100 and 300 eggs over several days, and the male then fertilizes them.

Air breathing

Polypterids, like bichirs, have special paired lungs connected to their throats by a glottis. These allow them to breathe air from the surface when the water around them doesn’t have enough oxygen. Their lungs work by pulling in air and sending oxygen-rich blood back to their bodies. Unlike many other fish or land animals, their lungs are smooth sacs and not filled with tiny air pockets. Bichirs have a special way of breathing called "recoil aspiration," and they often use tiny openings on the top of their heads called spiracles to breathe when they are resting or in very shallow water.

Polypterids as aquarium specimens

Polypterids, also known as 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 belong to 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.