What size tank do you have for them?
If you go with the more common African mudskipper, you'll need a somewhat large tank, especially if you get more than one.
Frank'saquarium has Indian dwarf mudskippers (Periophthalmus novemradiatus) They grow to 4". You could keep up to 6 in a 30 gal due to their relatively sociable nature, or two or three more in the 55 gal. I'd go with the 55 gal. More space is always better.