Class Osteichthyes: Characteristics & Examples

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Osteichthyes Circulatory System

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:00 Classifying Organisms
  • 0:41 Osteichthyes Facts
  • 1:28 Osteichthyes Characteristics
  • 2:17 Osteichthyes Subclasses
  • 3:32 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Ebony Potts

Ebony has taught middle and high school physical science, life science & biology. She's also been an assistant principal and has a doctorate in educational administration.

In this lesson, we take a look at a specific class of fish called Osteichthyes. We'll cover the characteristics of its members, see some examples, and find out what makes the two subclasses of this group of fish so unique.

Classifying Organisms

Have you ever peered into an ocean or lake and thought about all the different types of life that live beneath the surface? It may not look like it from standing on the shore, but oceans, lakes, and rivers are teaming with life. Whales, sharks, coral, sea lions, fish, and many other organisms call the earth's waters home.

Just like on land, scientists have classified marine organisms and grouped them based on their similarities and differences. All organisms are divided into interrelated groupings called kingdoms, phyla, classes, orders, families, genus, and species. The majority of fish fall into one class, called Osteichthyes, which is the focus of this lesson.

Osteichthyes Facts

There are over 25,000 species of Osteichthyes, or bony fish, in the earth's waters. Most of them have a skeleton made of bone that is much stiffer than cartilaginous fish, which have skeletons made of cartilage, such as sharks. With such an abundance of species, Osteichthyes are the largest group of vertebrates in the world and the largest class of organisms that live in the ocean. Osteichthyes account for about 96% of all the fish in the sea.

Osteichthyes have a keen sense of smell, but unlike other keen-smelling fish, they also have very good eyesight. Osteichthyes eat a wide range of foods: some are herbivores and some carnivores, and some can go long periods without any kind of food at all. In fact, the freshwater eel can go up to a year without food!

Osteichthyes Characteristics

There are exceptions, of course, but generally all Osteichthyes have a variety of shared characteristics. Since bony fish have a heavier skeleton than cartilaginous fish, they have a special adaptation to keep them from sinking, known as a swim bladder. A swim bladder is a gas-filled organ located under the skeleton. The trapped gas helps keep the fish buoyant, very much like how the air in a life jacket helps you float.

Osteichthyes also have an operculum, which is a bony structure that covers the chambers near the gills on each side of the fish. The operculum allows the fish to breathe without swimming. They move the bone back and forth to pull and push water past the gills, providing them with oxygen. Other shared characteristics of Osteichthyes include skin with mucous glands, dermal scales, paired fins, and jaws with teeth.

Osteichthyes Subclasses

Osteichthyes are divided into two subclasses: Sarcopterygii and Actinopterygii. Sarcopterygii, or lobe-finned fishes, include the lungfish and the coelacanth, and Actinopterygii, or ray-finned fishes, include salmon, herring, eels, anchovies, and clownfish, among many others.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account