Do betta fry scavenge off the bottom? Mine are little over 2 days old and free swimming. I can't tell if they're eating or not. I've put a little bbs in there and some egg yolk. They for the most part are just cruising at the bottom. I'm using a 10gal half full when would be a good time to do a water change? I can barely see them and don't want to suck them up.