Hello Paul I know that in the past when spawning ordinary kribs, that in more acid water I ended up with more females then males and vice versa, in alkaline water I ended up with larger % of males. Don't know about pH swings in P T Moliwe. Last winter when I spawned them, I had pretty much even numbers of male/females in my tap water with a pH of around 6.6. Hope this helps. John ------------------------------------------------------------------------- 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. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!