Wow..who knew? There are so many variables to this hobby..it is really tough to blanket each fish with a description as they can all be different. This person might feed their tank flakes for all we know, and the fish are simply hungry. Just like they say hawkfish are shrimp killers, I'm sure it has happened, or they would'nt have gotten that reputation. But I have kept one with shrimp from sexy shrimp, anemone shrimp to larger cleaners and pepps without issue. I would'nt have thought cards as being that way, but true too I mostly work with juvenile fish.