Slowpokes of the sea, frogfish and handfish barely manage to swim
Frogfishes were mistaken for true frogs in the 18th century, which isn’t as silly as it sounds. These are strange fishes. And the first genetic study of their evolutionary relationships raises 21st century puzzlements over how to classify them.
“I tell people they’re fish that can’t swim,” says Rachel Arnold of the University of Washington in Seattle. That’s only a slight exaggeration: “They’re kind of wagging their tails, trying to push themselves through the water, but they’re just not going very fast,” she says.
The fish can get an assist by gulping water and jetting it out of the small opening behind their gills. “It sounds like it might be fast — ‘jet propulsion,’ right? — but it’s still remarkably inefficient,” Arnold says.
Instead of swimming, the several dozen