Finally I've understood the difference I have now one panduro female (bought today), one nijsseni female, one nijsseni male. The difference as Mike and as Romer said is very easy to see in the mouth shape. Even the colours can be an easy way to determine the sex, but as some of you said that cannot be taken as a rule. Anyway I now have a mix on the tank, hope the male stop killing everything and decide to do something with the right apisto :-)) Take care Bye and thanks to all of you Simone Vicini (svicini@lcnet.it) ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@majordomo.pobox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@majordomo.pobox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!