University of Florida
University of Florida: Body Features of Sharks
Somewhat shark specific, but a great look at the external anatomy of these cartilaginous fish.
Other
Look d.com: Fish Anatomy
This site, which is given by LookD.com, provides a basic overview of fish anatomy. The information is medium in length, and factual, making it worth checking out on the subject.
Other
It's Time for a Change
Observe a juvenile red-tailed hawk as it molts into its new adult feathers.