growth ring

…in shape, and they exhibit growth rings. Ctenoid scales resemble cycloid scales but have comblike teeth on their overlapping edge.

…arranged in an overlapping pattern; growth rings are evident on the free edges. Ctenoid scales are similar to cycloid, except that they have spines or comblike teeth along their free edges; these scales are characteristic of the higher bony fishes—perches and sunfishes, for example. Some fishes, such as catfishes and…