University of Florida
Florida Museum of Natural History: Ichthyology: Fish Groups
Provides information on, and photographs of, the primitive fish classes. Discusses the Superclass Agnatha, the Class Chondrichthyes, and the Osteichthyes. Very interesting, with lots of pictures!
Other
The State of Iowa: Fishes of Iowa
Use this resource to learn the many types of fish that can be found in the state of Iowa. Near the bottom, click on a fish family name and get a very detailed description of the fish that are part of that family.