Some important tips for identifying freshwater fish

Andy Whitcomb

An important part of fishing is just knowing what types of freshwater fish you have caught. Fish identification can be tricky depending on where you are fishing. In general, the larger the body of water, the more diverse the fish community. A farm pond can only have three or four species, while a river system can contain a hundred species of freshwater fish. Here are some tips for identifying freshwater fish.

Fish color can be helpful, but it shouldn’t be the only trait in identifying freshwater fish species. Habitat factors such as water opacity and vegetation type can influence the color of a species. Fish names can also be misleading, as a green sunfish may have more distinct blue “gills” (lids) than bluegill, and a black crappie may not appear darker than a white crappie.

The most important approach to identifying freshwater fish is to study the actual anatomy of the fish. Not all fish are built equal. Some fish have obvious distinguishing features such as the “whiskers” on each catfish. Also note other proportions such as the ratio of length to height, and the size and shape of the mouth and fin. In a flat-headed catfish, for example, the lower lip protrudes above the upper lip.

Many freshwater fish have more subtle distinguishing features. Our guide to freshwater fish identification can help you examine different types of freshwater fish species and identify the exact type of freshwater fish. For example, to determine if it is a white or black crappie, count the spines on the back. The black crappie has 7 or 8 dorsal spines, while the white crappie usually only has 6. With practice, you may even be able to identify hybrids like the pikeperch / sucker cross, Saugeye, that have characteristics of both.

Learning to identify your freshwater fish will help as you share the admiration of each species with fellow anglers and even spot protected or invasive species. It’s also important when it comes to regulations. When you renew your fishing license, get a copy of the state fishing regulations. Although common names may vary from region to region, pay attention to the names of the freshwater fish species listed in this publication to avoid regulatory issues and to know where to fish for specific fish species.

Andy Whitcomb

Andy is an outdoor writer ( and stressed out dad has contributed over 380 blogs to since 2011. Born in Florida but raised on the banks of farm ponds in Oklahoma, he now hunts pike, small bass and steelhead in Pennsylvania. After completing his Bachelor of Science degree in zoology from OSU, he worked in fish hatcheries and as a fishery research technician at OSU, in the US state of Iowa and Michigan.