It looks like a fish. It swims like a fish. But it isn’t a fish.

It’s SoFi, the robotic fish.

Developed by researchers at the Massachusetts Institute of Technology, SoFi is a soft-bodied robot that glides silently through the water with a smooth, undulating motion designed to mimic the movements of real fish.

It is the first robotic fish to contend with pressures of an actual ocean setting for an extended period of time.

In a study published Wednesday in Science Robotics, the authors describe how SoFi can nimbly navigate a coral reef off Fiji in three dimensions, swimming up, down, left, right and forward, all at the behest of a diver armed with what looks like a Nintendo controller.

The authors also report that the robot can handle water depths of about 60 feet, and appears to swim alongside real fish without spooking them.

“For us, this fish is magical,” said Daniela Rus, director of the Computer Science and Artificial Intelligence Laboratory at MIT, who led the work. “We imagine someday it might help us uncover more mysteries from the amazing underwater world that we know so little about.”

SoFi is a fairly small robot, about a foot and a half long and weighing just 3.5 pounds. A hydraulic pump moves water in its soft rubber tail from side to side, allowing it to swim in a fishlike motion.

Rus’ ultimate goal is to create an instrument that can help biologists study ocean animals in an unobtrusive way.

“With this robot, I hope we can begin to peek into the secret lives of underwater creatures,” she said.