Periophthalmus is the core genus of mudskippers, amphibious gobies found across mangrove forests, mudflats, and estuaries of the Indo-Pacific and, in one case, the Atlantic coast of Africa; the atlas's 10 species draw on Indonesia, Malaysia, Thailand, India, Myanmar, the Philippines, Singapore, and Vietnam. Mudskippers are famous for spending long stretches out of water: paired pectoral fins act like small limbs for hopping and "walking" across exposed mud at low tide, and the fish breathe partly through their skin and the moist lining of the mouth and throat while carrying a reservoir of water in their gill chambers. Raised, mobile eyes sit high on the head for all-round vision above the waterline, one of the most recognizable adaptations in any fish. Atlas species run 1.5–6 in.
Mudskippers occupy a genuine specialist niche in the hobby, kept in paludariums with a sloping land area, shallow brackish water, and high humidity rather than a conventional tank, since they spend most of their time out of water. Periophthalmus barbarus, the Atlantic mudskipper, stands out as the genus's one Atlantic-coast species against an otherwise Indo-Pacific spread, and shows up periodically in specialist trade alongside more common Indo-Pacific species. Conservation status leans favorable where assessed (5 Least Concern), with several species Not Evaluated or Data Deficient - unsurprising given how patchy survey coverage of mangrove specialists tends to be across such a wide range.