Fish belong to the subclass Pieces under the Class Chordata.
They are characterized by gills, fins, and digit-less limbs.
Fishes have a variety of scales covering their body.
Fish scales are formed of bone from the deeper, or dermal, skin layer.
The scales serve the function of protecting the fish against predators as well as providing them the ability to locomote swiftly by avoiding friction against the water.
However, there are certain types of fishes that do not have scales – these scale members of the catfish and clingfish family.
