One of the adaptation of fish is the presence of scales upon their skin. These scales  protect their skin from attacks by predators ,parasites and other injuries .The morphology of  a scale is used to identify the species of fish it came from .Cartilaginous  fishes are covered with placoid scales. Bony fishes are covered with cycloid, ctenoid or ganoid scales.

Some of the scales of bony fishes were observed under the foldscope and were found to have cycloid scales.