Saltwater fish species identification

Updated April 10, 2017

Saltwater fish are present in all marine environments, with thousands of species worldwide. In the United States, saltwater fish species identification is especially important when fishing, because some fish are game fish, and others are not. Coastal waters play host to thousands of different fish varieties, so knowing how to identify species in a specific area is absolutely essential.


One of the most important reasons for accurate saltwater fish species identification is because there are often legal restrictions on the types of fish that you can catch. Species classified as game fish are typically safe for you to catch and keep, but many areas have specific regulations for what size fish or how many fish of a specific species you can catch. These regulations make accurate fish identification vital.


Region plays an important part in saltwater fish species identification. For example, along the coast of Florida there are more than 1,000 marine fish species, 40 of which are regulated, and only six of which have game fish status in the state. The fish species that you are likely to encounter will be dependent on the region where you are fishing. A fish species field guide for your state or region is a vital tool when fishing.

Size and Shape

Size and shape play an important role in fish identification, since they are some of the most readily-observed details. Though scientists use length to determine size and age, most anglers rely on weight for identification, especially when it comes to record-keeping. Shape also plays a role in fish identification, including fin and ray counts which can impart vital clues as to a species' identification. The Southern Flounder, for example, is a flat-bodied fish, while the bonefish is long and slender, and the ling is shaped similarly to a spindle.

Physical Characteristics

Many saltwater fish have similar appearances, with only small physical differences between them. The inside of the spotted seatrout's mouth is orange and has distinctive canine-like teeth. The Atlantic croaker has barbell whiskers in a row on each side of the lower jaw. Gulf flounders have a set of three prominent eyespots that form a triangle. Red groupers have scarlet-orange linings around their mouths and disorganised blotches on their sides. These colour and pattern differences can aid significantly in identifying specific species.

Behavioural Characteristics

Behaviour and feeding habits can also play a role in saltwater fish species identification. Sheepshead are mainly found near oyster reefs, jetty rocks and pier pilings. Red drums prefer shallow waters in bays while black drums tend toward deeper waters of 100 feet or more. The American shad spawns in freshwater, and its colours darken during spawning season. Small differences in habitat, feeding habits and other behaviour can give vital clues to the identification of species.

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About the Author

Jennifer Uhl has been writing professionally since 2005. She writes primarily for the web and has been published as a ghostwriter in "Tropical Fish Magazine" and "Entrepreneur." She is pursuing a Bachelor of Science in health care from Mira Costa College.