Only downside I see is that I don't see mine very often. They like to hide most of the time. However, they are great at getting rid of algae and many will eat bubble algae. I may even add another one down the road.
Nice addition. They do stay fairly small and *normally* do not bother anything. They are very interesting to watch when they come out. Mine usually waits until lights out or just actinics to show it's face.
Are you sure it died? I rarely see mine and wondered at first if it had died. It just suddenly appeared one day. Then it was gone again. I see it every two or three weeks, happy and picking at rocks.
i have had bad luck keeping emerald crabs alive, recently i added 2 to my 75 gallon and its been a month now and there still alive so gettin lucky this time.
I haven't had any problems with mine yet all he does is stroll around and pick every piece of algae he can...mine has a broken claw he has like 1 full one and 1 that is only 1 stem? or whatever, will this grow back? I think it probably broke when the guy at the lfs was netting him out.