if they eat the shredded shrimp you might try other dead stuff, maybe crickets, earthworms, mealworms, superworms, nightcrawlers, crayfish, minnows. they also eat fruits and veggies, maybe it's the color they like, mine doesn't like the color red, why knows why, but just doesn't. try lots of different things until you find what they will eat. some will eat anything while others will only eat a few things. there is a lot more things you could feed it so dont give up! you could try feeding:carrots, grapes (they like to play w/ these in their tank), squash, zuccini, peas, greenbeans, apples...