well.....im going away for 2 weeks and wont be home to feed my fish so i bought those 2 week slow release feeder things.. i would ask a neighbor or nearby family member but i dont want to bother them and i dont trust my neighbors all too well.. luckily i only have a couple of not too rare fish.. not rare at all. but if you can help like telling me if those things work .. i have 2 sharks, a pleco , a betta , and 3 emerald cory's.