Small-scale differences

Fish are incredible swimmers. The way they glide through the water, especially in some of Wyoming’s fast-moving rivers and streams, is breathtaking. Scales serve an essential function for all Wyoming fish species, but did you know that not all fish have the same scales?

Cycloid scales are the most common scale on Wyoming’s fish. Found on trout and carp, the round scales overlap with one another to form a protective layer around the fish. The scales reduce drag and allow these fish to swim quickly through the water.

Bass, perch and sunfish have a similar type of scale — the ctenoid scale. These scales are round and overlap like cycloid scales, but one edge of the scale has teeth. These teeth serve as an extra defense mechanism. They are typically combined with spiny fin rays, which make these fish especially difficult to handle.

Ganoid scales are unique. Found only on shovelnose sturgeon in Wyoming, these scales are composed of several layers that culminate in a thick, bony shell. Ganoid scales do not overlap. Instead, they fit together like a jigsaw puzzle to create an almost impenetrable armor.

Some fish, like catfish, don’t have scales. These fish rely on slime or individual protective components, like the spine behind a catfish's head, for protection. Fish without scales generally stay in murky water away from predators and use their sense of smell to find food.

Although all fish live in water, they employ different strategies to protect themselves and move through the water efficiently. Next time you catch a fish, stop for a second and see what kind of scales it has.

Fall is a great time to catch fish, and even small ponds can have great fisheries. Not sure where to go? Check out our YouTube series on community fishing ponds to find one near you!