This is probably the best and most natural setup I've seen for fiddler crabs. I once kept a few in a half filled 10 gallon tank with brackish water, and they did very well for a long time. I only provided rocks and floating cork bark for land, but I think they definitely would have preferred burrowing space. The only reason they died was because I got tired of making brackish water...they really don't last long in freshwater.
I would recommend putting a layer of lava rocks under your sand to help keep the substrate aerated and from becoming anaerobic.
I would recommend putting a layer of lava rocks under your sand to help keep the substrate aerated and from becoming anaerobic.
