My new fish will eat the flakes broken down, but when I just cleaned out his tank I think every worm or shrimp was still there. I don't know if he is having trouble finding them or just unfamilar with them being food. After a week he still does not come to the opening to get food like my other betta. Is active and moving - does not appear to be sick. Would one of those food rings help? My other fish just waits for me in the morning and evening and (and any other time during the day he can catch my eye). At first was leary of the the bubbles but seems ok with them now. Is a 2.5 tank so not really a large filter just the gravel filter thing.