Something makes me think a waspfish wouldn't go well with knight and violet gobies. I might be mistaken though.
Once I get the 125 gallon tank to move my violet and bumblebee gobies, I want to move my other fish to the 55 gallon tank, freeing up the 20 gallon. I want to turn the 20 gallon tank into an Indian mudskipper tank. on Franksaquarium, they're only $7.
I know of a tropical fish store that has two African mudskippers, but they get big and cost $38.