I have 3 of them. So far they have remained peacefull. So far my ottos have been left alone, along with the 3 remaining cardinal tetras and a lone ember tetra. I do dump about 100 ghost shrimp in about once every 2 weeks, and they do eat them. Most of the time they have been hiding, but have learned to associate me with food and will come out when I am around. I feed them bloodworms and other frozon food.