Mudskipper (Periophthalmus sp.) in mud. This amphibious fish inhabits estuaries and swamp habitats. It moves across land using its limb- like pectoral fins. It breathes on land using highly vascular sacks on its mouth and gills. Its skin contains cells that are filled with a watery fluid, which cushion its movements. Its protruding eyes are adapted for vision above the water. Photographed in Sabah, Malaysian Borneo.