Oh than you definatly shouldnt feed them those worms from your yard. You can but them from petsmart. And about using worms from bait stores, I have read numerous articles on how bait store worms usually have tons of potentially harmful bacteria in their intestines from crap that they consume which can possibly harm your fish. So i would just be careful with bait shop worms. And you dont need to use oatmeal if you dont have any, you can simply place the worms in a plastic container that has a moist bottom overnight so that they excrete watever junk is in their system.