I was at a lfs just looking around and I noticed they have fiddler crabs completely underwater. They seem fine, but I read online that they need land too. I am interested in them for my 29g tank (cycling right now). So I was thinking of driftwood up to some sort of enclosed structure on the top of the tank. I can pretty easily make a plexiglass box for the top part of my tank. So if I make a rock or driftwood structure from the bottom of the tank to the top and out into the addition, do you think that they would clime all the way up there? Do they need some sort of lighting up there as well? What would I put for "flooring"? Would normal gravel be good, or should I put sand or something? I would probably have to clean it somehow. Is there a temperature or humidity range that added land would have to be at?