Osteichthyes Facts for Kids

Quick facts for kids Bony fish Temporal range: Late Silurian - Recent

Atlantic herring
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Infraphylum:	Gnathostomata
Superclass:	Osteichthyes Huxley, 1880

Osteichthyes are a huge group of fish often called bony fish. They include two main types: the ray-finned fish and the lobe-finned fish. These two groups started to develop separately about 440 million years ago.

Bony fish are the most diverse group of animals with backbones. There are over 29,000 different kinds of bony fish. This makes them the largest group of vertebrates alive today!

What are Bony Fish?
- Ray-Finned Fish
- Lobe-Finned Fish
Where do Bony Fish Live?
How do Bony Fish Survive?
Images for kids
See also

What are Bony Fish?

Bony fish get their name because their skeletons are made mostly of bone. This is different from cartilaginous fish, like sharks, whose skeletons are made of cartilage. Bony fish live in almost every water environment. You can find them in fresh water like rivers and lakes. They also live in salty ocean waters, from shallow coasts to the deep sea.

Ray-Finned Fish

Most of the fish you know are ray-finned fish. This group is called Actinopterygii. Their fins are supported by bony spines or "rays." These rays spread out from the base of the fin. This design helps them move easily through water.

Ray-finned fish are incredibly diverse. They come in all shapes and sizes. Some examples include:

Tuna, which are fast swimmers in the open ocean.
Goldfish, which are popular pets.
Eels, which have long, snake-like bodies.
Seahorses, which have unique upright bodies.

Lobe-Finned Fish

The other main group is the lobe-finned fish, also known as Sarcopterygii. Their fins are different. They have a fleshy, muscular base with bones inside. These bones are similar to the bones in the limbs of land animals.

There are fewer types of lobe-finned fish alive today. The most famous ones are:

Coelacanths: These are often called "living fossils." They were thought to be extinct for millions of years. Then, they were rediscovered in the 20th century.
Lungfish: These fish have lungs, just like land animals. This allows them to breathe air. Some can even survive out of water for a while.

Lobe-finned fish are very important in evolution. Scientists believe that land animals, including humans, evolved from an ancient group of lobe-finned fish. This is why they are sometimes included when talking about the larger group of bony fish.

Where do Bony Fish Live?

Bony fish live in almost every watery place on Earth. They are found in:

Freshwater environments like small streams, large rivers, and deep lakes.
Saltwater environments, from warm tropical reefs to cold polar seas.
Shallow waters near the coast.
The deepest parts of the ocean, where no sunlight reaches.

They have adapted to many different conditions. Some can live in very cold water. Others thrive in hot springs. Some can even live in water with very little oxygen.

How do Bony Fish Survive?

Bony fish have many features that help them live in water.

Gills: They use gills to breathe. Gills take oxygen from the water.
Swim Bladder: Most bony fish have a swim bladder. This is a gas-filled sac. It helps them control their buoyancy. This means they can float at different depths without much effort.
Scales: Their bodies are covered in scales. These scales protect them. They also help reduce drag when swimming.
Lateral Line: Many bony fish have a special sense organ called a lateral line. This line runs along their sides. It helps them detect movements and vibrations in the water. This is useful for finding food and avoiding predators.

Images for kids

Guiyu oneiros, the earliest known bony fish, lived during the Late Silurian, 425 million years ago. It has a combination of both ray-finned and lobe-finned features, although analysis of the totality of its features place it closer to lobe-finned fish.
Ocean sunfish is the heaviest bony fish in the world
A Coelacanth, a type of lobe-finned fish.
A Queensland lungfish, another lobe-finned fish.
An example of a tetrapod, which evolved from lobe-finned fish.
A Bichir, a type of ray-finned fish.
An Atlantic sturgeon.
An Amiiformes fish.
A Longnose gar.
An Elopiformes fish.
An Albuliformes fish.
A Notacanthiformes fish.
An Eel, a type of Anguilliformes fish.
An Osteoglossiformes fish.
A Herring, a type of Clupeiformes fish.
An Alepocephaliformes fish.
A Gonorynchiformes fish.
A Carp, a type of Cypriniformes fish.
A Characiformes fish.
A South American knifefish, a type of Gymnotiformes fish.
A Black bullhead, a type of Catfish.
An Argentiniformes fish.
A Salmon, a type of Salmoniformes fish.
An Osmeriformes fish.
An Anglerfish, a type of Stomiiformes fish.
A John Dory, a type of Neoteleostei fish.

Osteichthyes facts for kids

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