I got a baby betta from petco about a month ago. Im having a really hard time sexing him/her. Ive never seen it flare so I cant go by watching it flare and look for a "beard". What I have noticed in the month Ive had it is: Its fins are getting pretty long. It has really long ventral fins. As it ages its color is getting brighter. When I first got it its body was pretty light colored and it had horizontal lines running across the body. Now its getting quite bright and I rarely see the lines anymore, though they are still there. Ive added a picture, however its pretty poor quality. Taken with a cell phone. Plus, the little bugger never stays still so is hard to photgraph.