What is the difference between 3 types of fish?

* Have a bony skeleton

* Most abundant group of fish, with over 29,000 species

* Examples include tuna, salmon, and bass

2. Cartilaginous fish (Chondrichthyes)

* Have a cartilaginous skeleton

* Include sharks, rays, and skates

* Have a higher concentration of urea in their blood, which helps them maintain buoyancy

3. Jawless fish (Agnatha)

* Do not have jaws

* Include hagfish and lampreys

* Are the most primitive type of fish