Scales

Horny or bony plates arranged in overlapping rows on the body of the fish, the free rear end of a scale covering the front end attached to the scale behind it. In a number of species, the scales are thickened and form true bony plates. For others, however, they are minor (eels). Fish of a given species keep the same number of scales all their life. Aging does not cause an increase in the number of scales, but the growth of the scales themselves. The scales cover the entire body of the fish (except fins). They are fully covered by a very thin and fragile skin.