Ok what are water changes?? lol Just kidding ppl, I get alot of these bubbles when doing water changes in winter time, i also think its higher content of disolved O2 due to using colder water out of the pipes in winter. Never had it harm my fish either. 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://www.digital.com for "Apistogramma Mailing List Archives"!