Perhaps you are thinking from the title of this commentary that it deals with methods of estimating relative abundance or the size of a particular fish population. However, it is far from that. The title is borrowed from a classic children’s book by Dr. Seuss: One Fish Two Fish Red Fish Blue Fish (Seuss 1960). This column is about the importance of fish identification and naming. I am probably like many of you by having an innate fascination with the tremendous diversity of aquatic species. I want to know what species of fish it is that I am seeing, whether it is in an aquarium, in a pile on the deck of a research trawler, or on display in a fish market far from home. Showing my northeast United States bias, I have accumulated a shelf full of fish taxonomy books that includes the ageless and updated classics Freshwater Fishes of Canada (Scott and Crossman 1973) and Bigelow and Schroeder’s Fishes of the Gulf of Maine (Collette and Klein-MacPhee 2002). There are countless books of fishes of a particular region or state like Fishes of Alaska (Mecklenburg et al. 2002) or Freshwater Fishes of Virginia (Jenkins and Burkhead 1994). Other books specialize in particular species groups like Trout and Salmon of North America (Behnke 2002) or categories of fishes like Nonindigenous Fishes Introduced into Inland Waters of the United States (Fuller et al. 1999). The AFS online bookstore (fisheries.org/bookstore) is a great source for many publications like these. As Society members, we are aware of the dilemma that common names present to fish identification. For example, a rockfish can be very different species depending on where it is located. On the Pacific Coast, it is likely to be a member of the genus Sebastes; on the Atlantic Coast, it is a Striped Bass Morone saxatilis; and in the Mediterranean, it is likely to be the Maderia Rockfish Scorpaena maderensis. Dr. Seuss’ red fish could be an Ocean Perch Sebastes alutus in New England or a Red Drum Sciaenops ocellatus in the Gulf of Mexico. The Integrated Taxonomic Information System (ITIS; itis.gov) includes common names for fishes within a total of about 700,000 animal, plant, fungi, and microbe species. My master’s work was on Alewife Alosa pseudoharengus, which ITIS also lists as Bigeye Herring, Branch Herring, Freshwater Herring, Gray Herring, Grayback, Kyak, Sawbelly, and White Herring. Other common names for this species, from several of the fish taxonomy books that I mentioned above, are Gaspereau (French), Glut Herring, Mulhaden, Blear-eyed Herring, Spring Herring, Golden Shad, Seth, Green Shad, Skipjack, Bang, Racer, Ellwife, and Wall-eyed Herring. But perhaps the most universal common name for this species is river herring, which lumps this species together with the closely related Blueback Herring Alosa aestivalis. So the diversity of common names can be quite impressive. AFS has a Names of Fishes Committee that is responsible for matters pertaining to the common and scientific names of fishes. This joint committee with the American Society of Ichthyologists and Herpetologists maintains a checklist of names to achieve uniformity and avoid confusion in nomenclature. Most recently, the committee published the AFS list of Common and Scientific Names of Fishes from the United States, Canada, and Mexico, 7th edition (Page et al. 2013). The committee reviews all papers that have appeared between editions for potential changes. Their work is important since a very basic need of fisheries professionals is to know exactly what species or subspecies we are talking about. Fish identification is particularly important when these fish species are under various endangered species protections. There was a recent request by the Arizona Fish and Game Department for the committee to do a scientific review of the species-level diversity of chub in the lower Colorado River Basin. The three current species of Gila are Gila Chub G. intermedia, Roundtail Chub G. robusta, and Headwater Chub G. nigra, with the first species federally listed as endangered and the other two species being candidates for federal listing. The taxonomy of this group is particularly difficult because of hybridization and conflicting results of genetics studies. The committee is planning on meeting in Arizona in spring 2016 to tackle this work. There is a unique program in Australia called Redmap (redmap.org.au) for online submission of observations of unusual fish and other marine life by fishers, divers, and others. The photographs that are submitted, and later verified by biologists, are key to solving common name problems. These types of programs are increasingly important as climate change continues to affect aquatic habitats and species distributions. So try to keep up that childhood enthusiasm for fishes and other aquatic species as espoused by Dr. Seuss. This means getting out in the field to see live specimens instead of digital images on the Internet. AFS and others have tools to help with nomenclature and identification, but it’s up to you to put them into use. REFERENCES Behnke, R. J. 2002. Trout and salmon of North America. The Free Press, New York. Collette, B. B., and G. Klein-MacPhee, editors. 2002. Bigelow and Schroeder’s fishes of the Gulf of Maine. Smithsonian Institution Press, Washington and London. Fuller, P. L., L. G. Nico, and J. D. Williams. 1999. Non indigenous fishes introduced into inland waters of the United States. American Fisheries Society, Special Publication 27, Bethesda, Maryland. Jenkins, R. E., and N. M. Burkhead. 1994. Freshwater fishes of Virginia. American Fisheries Society, Bethesda, Maryland. Mecklenburg, C. W., T. A. Mecklenburg, and L. K. Thorsteinson. 2002. Fishes of Alaska. American Fisheries Society, Bethesda, Maryland. Page, L. M., H. Espinosa-Perez, L. T. Findley, C. R. Gilbert, R. N. Lea, N. E. Mandrak, R. L. Mayden, and J. S. Nelson. 2013. Common and scientific names of fishes from the United States, Canada and Mexico, 7th Edition. American Fisheries Society, Special Publication 34, Bethesda, Maryland. Scott, W. B, and E. J. Crossman. 1973. Freshwater fishes of Canada. Fisheries Research Board of Canada, Bulletin 184, Ottawa. Seuss, D. 1960. One fish two fish red fish blue fish. Random House,New York Members click below for the March 2016 Fisheries magazine’s complete