I stumbled across this FDA website while searching for info on a specific fish.
What is it?
"The Regulatory Fish Encyclopedia (RFE) is a compilation of data in several formats that assists with the accurate identification of fish species. It was developed by FDA's RFE Team to help federal, state, and local officials and purchasers of seafood identify species substitution and economic deception in the marketplace.
The RFE includes for each of a number of commercially relevant fish species for sale in the U.S. market high-resolution photographs as their scanned digital images (jpeg format) of whole fish and their marketed product forms (including fillets, steaks, or whole crustaceans) which may be used for visual comparison to a whole fish in question (or its marketed product form). The RFE also includes unique taxonomic characteristics (physical properties such as size, shape, color, etc.), usually in a "checklist" format, to aid in identification. In addition there is chemical taxonomic information consisting of species-characteristic biochemical patterns which may be compared quantitatively to patterns obtained by an appopriate laboratory analysis of the fish species specimen in question. These patterns include data from IEF (isoelectric focusing and RFLP (restriction fragment length polymorphism) studies."
There's even plans to add DNA pattern graphics!