Being able to keep them in a smaller species tank would be ideal in my opinion. In a reef tank with other fish, it's hard to find tank mates that will help take care of the tank, and not be too large, or to small to be in with the Angler. Feeding can be a little bit of a chore, but I think watching them eat is why most people get an Angler to begin with. They produce a moderate amount of wastes, and do nothing to help keep your tank clean or pest free. Say you have a case of Flatworms, like I do now, it's almost impossible to find a fish that is known for controlling them that would be large enough not to get eaten by an Angler. Also if your tank has an algae problem, like mine also does, it's hard to find fish (in my case-54gal) that are big enough to avoid getting eaten, and small enough to fit in the tank and that help out with algae. Other than that, i've found it to be quite hardy. My tank has been through a somewhat mini-crash, and i've switched tanks and moved the rock around alot, and all the while the Angler seemed fine. I finally have my tank and rock set how I like, so it's become much more stable.