The pygmy seahorse is both tiny and well camouflaged. It is very difficult to spot amongst the sea grasses, soft corals, or gorgonians (sea fans) that it inhabits. Other distinctive pygmy seahorse characteristics include a fleshy head and body, a very short snout, and a long, prehensile tail. With their short snouts, they have the appearance of baby animals. Pygmy seahorses are 14–27 millimetres (0.55–1.06 in) long from the tip of the tail to the end of the snout, so that their vertical height while swimming is still smaller. An adult may be as small as 13 millimetres (0.51 in) long. True pygmy seahorses have distinctive morphological markers. Unlike other seahorses, they have a single gill opening on the back of the head, instead of two on the sides. Males brood their young in a pouch on their trunk. Males and females are distinguished by openings at the bottom of the trunk: females have a tiny, raised round pore for extruding eggs and males have a fore-and-aft slit for accepting them.