This fish spends most of its life out of water, walking on land

Mudskippers are small fish that live along the muddy and mangrove coastlines of the tropics, spending most of their active life out of the water, on mudflats exposed at low tide.

They move across land by pushing themselves along with strong, muscular pectoral fins that work almost like a pair of primitive legs — they can even hop, and climb up mangrove roots.

Out of water, they breathe mainly through their skin and the lining of their mouth, as long as those stay moist — which is why they regularly roll around in mud or puddles, to avoid drying out and suffocating on land.

The bigger picture: mudskippers are a living example of what the first vertebrates crawling out of the water onto land might have looked like hundreds of millions of years ago — a living illustration of one of evolution's biggest steps.