The giant mudskipper Periophthalmodon schlosseri is one of the largest of mudskippers. It prefers mangrove habitat, and is often seen clinging to mangrove tree roots. It ventures out onto adjacent mudflats at low tide, keeping near the water's edge as the tide falls.

The species is identified by its pale to dark brown body colour, adorned with a black lateral stripe on each flank extending from the eye to the base of the tail (though in some specimens the black stripe may be less apparent). Some specimens or populations have dark banding across the back, extending to the flanks.

The cheeks are patterned with numerous pale bluish-white speckles, which are also present on the flanks though fewer in number. The front dorsal fin is reddish-brown, and the rear dorsal fin is dark, with a pale base. Both have a white or cream margin.

Giant mudskippers feed mainly on invertebrates in the intertidal zone, particularly small crabs. However, they have also been observed taking other, smaller mudskippers of different species.

Like the blue-spotted mudskipper Boleophthalmus boddarti, they build extensive burrows in soft mud. These are marked by depressions in the substrate up to a metre across, which remain water-filled at low tide and are fiercely defended from rivals.

Periophthalmodon schlosseri occurs in various parts of Southeast Asia including Indochina, Thailand, Peninsular Malaysia, Singapore and parts of Indonesia.