[kuplakrabs]

I use silk and plastic in my tank. A word of caution though-some silk plants may leak dye into the water should they come in contact with it-especially the cheap dollar store plants. I'm sure that can't be too good for them LOL.

Some silk and plastic plants also have a wire inside to allow for easy positioning-you may want to avoid these as well. If the wire becomes exposed (from too much bending or the crabs pinching), you run the risk of it rusting in the humid tank conditions. I'm not saying your crabs are going to be harmed by the wire specifically, but it may be a good idea to avoid metal of any kind in the tank.