A fish that walks sideways — and moonwalks backward!

Professor Pip crouched by the riverbank, his fluffy tail swishing behind him, magnifying glass pressed to a shallow glass tank. Inside the tank, something extremely peculiar was happening: a fish was walking.

"Curiouser and curiouser!" he whispered.

Mia and Leo scrambled over on their knees. "Fish don't walk!" Leo insisted.

"Ah, but SOME do," said Pip. "This little fellow is called an armored searobin. And down in the deep, dark ocean, scientists just filmed one of his cousins doing something no other fish on Earth is known to do."

"What?!" both children said at once.

Pip's spectacles slipped down his nose. He grinned. "He moonwalks. Backward. On the seafloor."

Leo burst out laughing. "That's not a real thing!"

"Precisely a real thing! Watch." Pip pointed. Inside the tank, the little searobin fanned out its front fins, then poked six stiff, finger-like rays into the sand. It scuttled sideways with a jerky step-step-step, exactly like a crab.

Mia's mouth dropped open. "It has FINGERS?!"

"They're called fin rays," said Pip, "and in this fish, they're extra thick and stiffened. Most fish use fins to swim. This one uses them to walk. Try it yourselves — hands and knees, everybody!"

The children flopped onto the grass, palms and knees down. "Now shuffle sideways… good! Now try going backward."

Leo shuffled backward and immediately toppled over, giggling. "It's HARD!"

"Exactly!" beamed Pip. "It's hard for us because our bodies weren't built for it. But this fish's body was. His two big pectoral fins fan out like little wings — that helps with balance. And he has fluffy branches on his snout that work like whiskers, so he can feel his way along in the pitch dark."

"So he can't really see down there?" asked Mia.

"Not much! It's over a thousand feet deep — no sunlight reaches that far. So instead of seeing his dinner, he feels for it. It's called adaptation — when a creature's body is shaped just right for a really tough neighborhood."

He looked out at the shining river. "You know, humans have explored more of outer space than we have of our own deep ocean. Every time a submersible goes down, we find creatures we never even imagined."

Then he handed each child a smooth pebble. "Now you try. Set your pebble on the ground and imagine you are a searobin. Which of your bones would need to change to walk on fingers instead of feet?"