clarity...or something close to it
This is the reason why people should not use F1 or P1 or whatever. These are just terms geneticists use to follow a trait through generations. Unfortunately, people do use them (incorrectly may I add) as follows: P = parental, i.e. starting pair usually from unrelated bloodlines (assumed). f1 = filal 1, i.e.- the offspring of the parental generation. F2 is the tricky one that everyone messes up on. Most use it to describe crosses between two individuals from the f1 generation. An F1 bred back to a parental is just considered a backcross and receives no moniker. If you brought in another frog from an unrelated group that was an F1 and bred it with an F1 from another group...then since they are unrelated this is a new cross and is back to P (parental) generation. Again, this is my conflict with using this labeling system. It only works if you are inbreeding animals and following SPECIFIC traits.