I have fished the SE United States coast for many years and now everything I catch I know whether it's edible or not.It takes a while for you to remember the names of fish and such because there are quite a number but mostly what I catch here are flounder speckled trout spots croakers pinfish red and black drum and bluefish.
If you are just starting out and start catching them just walk to the nearest guy fishing and ask him what it is.That will strike a conversation and maybe you can get some pointers.