rtc, tsn, and this hybrid will all regurgitate if you over feed them or something spooks them too much. If there are bones in what you feed them they can't digest they will also regurgitate those, much like owls, and other birds of prey, except not in a nice dry pellet, but an explosion of icyiness, lol. It's always fun to scoop half digested fish off the bottom of the pond, or fish skulls.