Good question but I keep hearing that mudskippers are very territorial and with a small tank size there should be only a few animals in the tank with it. I have a 15 gal. so ill probably try 1 mudskipper for just starting.
I gotta 15 Gallon for indian mudskippers (none yet) but inside i have a pebble shore anchoring a mini palm tree on the right, deep water in the middle, and a waterfall made out of flat rock on the left. Oh theres also a small turtle dock and misc. plants (fake and real) and an amazon background...