Porcupine puffer in a FOWLR tank killed every fish he could catch. A diamond back goby impossibly rearranged the sand eventually covering all corals on the sand until I fished him out, and an Eibli Angel that eventually killed every open brain or scoly I put in the tank. Thousands of dollars worth. Try as I might I can't get him out of the reef tank. My mistake was putting him in the tank in the first place and listening to those that said reef safe. The only problem I've had with a bicolor is that mine like to rest on or among the corals and damage them that way. They are supposed to be algae eaters but I haven't seen it.