Hi, I've got my betta with 2 cory cats, and they get along really well. The problem is, the betta steals the cories' food. I've tried feeding the betta (Doug) first, and dropping in the food for the cories while Doug is eating, but then he'll troll along the bottom and steal the other pellets. This is making him become quite fat, because he is eating much more than he is supposed to. Is there anything else I can do to get him to stop?