Periophthalmodon is a genus of large mudskippers - amphibious gobies in the mudskipper subfamily of the goby lineage - found across South and Southeast Asia and into northern Australia, from India and Bangladesh through Myanmar, Thailand, Cambodia, and Malaysia to Indonesia. Atlas species range from about 4 in up to 10.5 in, making this one of the larger mudskipper genera; the eyes are set high on a domed head, an adaptation for scanning above the waterline while the body stays flat against the mud.
Mudskippers in this genus spend much of their time out of water on intertidal mudflats and in mangrove creeks, breathing air through skin and mouth-lining as well as gills, and propelling themselves across exposed mud with muscular, crutch-like pectoral fins. Periophthalmodon schlosseri, the giant mudskipper, is the biggest and best-known species, an aggressive, territorial predator of small crustaceans and other invertebrates that digs and defends a burrow in the mud. These are specialist, brackish-to-freshwater fish rather than mainstream aquarium stock, kept mainly by paludarium and brackish-water enthusiasts who can provide an exposed, muddy haul-out area alongside the water.