As stated above if they are new to your tank it may take a few days to adjust. Bloodworms either fresh or frozen are really hard to resist. I feed mine a mixture of flakes, sinking wafers, Emerald entree frozen veggie mix, Frozen frenzy (lots of meaty foods), Frozen bloodworms, and cucumber slices. Not all at once mind you, but I keep a variety in the diet, just like I try to do my own. And every now and again they get a really special treat of a coule of snails. REALLY fun to watch em go after the snails!!