Yvan, Although I'm not really in genetics or a related field. I would like to venture a guess using logic. I know it should cause some interesting views unless there is a positive answer to your question? First if you have one fish which is a Wild Fish F0 Then you take a captive bred Fish F1 Well, I would think that because you are breeding wild back into the line F1 could also be described as the fist generation captive breed so I believe the combination of F0 + F1 would still result in a fish which was a 1st generation captive breed F1. Just my logic. I'm not afraid of being wrong but, at lease I will find out why if I am wrong. If I'm right well then I guess logic sometimes works. JerryB ------------------------------------------------------------------------- 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. ------------------------------------------------------------------------- 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