Can someone explain the F classification of fish to me? I.e. F1 F2 F3 ect

Actually F1 or more correctly G1 means 1st generation from wild caught and F2 or G2 means 2nd generation from wild caught. From the 3rd generation from wild caught and beyond the reference is normally to tank raised or domestic.
If a wild caught is bred with an F1 the offspring will be F2 and an F1 with an F2 the resulting fry are domestic or tank raised. Hence the interest with serious breeders to keep within the wild caught to F2 generations so the lines can be traced. The genetics are still strong in this range and generally tend to weaken as you get further away from it.

Ok I got it. I've seen F0 before so I take it that means Wild caught.

Yeah that would be wild caught.

Ok good to know. Oh one more thing why is it called F1 insted of G1?

Filial generation, "filial" designating the the parent-offspring relationship. F1 equals the first filial generation, F2 second filial generation, etc., removed from the original parent stock.

WYite

Thanks Ivan!