The genus Periopthalmus contains some very bizarre fish which can leave the water
and move around using their pectoral fins. They are found in all the world's tropical
regions, except America, living in the sandy areas of estuaries. Caring for them
in captivity requires an aquaterrarium rather than a simple aquarium; they need
a bank of sand, with a gentle slope allowing them to emerge from the water, which
should not exceed 15 cm or so in depth. Captive breeding is very rare. The two species
most commonly available commercially are P. barbarus (blotched mudskipper) and P.
papilio (butterfly mudskipper). Size: 10-12 cm.