The F0 thing probably started with an engineer somewhere. ask any non-engineer to count for you and they start 1 2 3 etc. ask an engineer and you get 0 1 2 3. I know this because I are an engineer ;) and we naturally apply Boolean logic to the world around us. I just can't understand why people think we are weird. David Y is correct in his interpretation. the F1 etc is a convention used by people doing genetic work whether they are working with fish or horses. We hobbyist have adopted the system and are applying it to our needs. Which is just as valid though it can get confusing (talking about betta and guppy aficionados). Also this comes from your side of the pond Helen, I think (most likely the wrong name) it was a German dude by the name of Mendelssohn who dreamed the whole system up in the first place. I don't see where there is a problem using F1 to designate the first generation from wild caught as it is in general use in this form among hobbyist. It may not be the most correct but if it works and we aren't misrepresenting our animals what's the big deal. Erick Who knows I'm probably just full of it anyhow :) ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@listbox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@listbox.com. apisto-digest@listbox.com also available. Web archives at http://lists.thekrib.com/apisto