I put my male n female betta with convict fry in my 10 gal. They are very active and love to eat the convict babies, stuffing their bellies till they are as round as marbles. My male n female get along fine, he pretty much ignores her actually... I havent seen him build a bubble nest either. I got my male from wallmart and my female from superpet. The container they had her in was reeeeeeeeeeeaally small, like less than 1/2 the size of the one they had my male in at wallmart. I was glad to get her out of there.