It looks like a fish, moves like a fish, but it’s definitely a robot. It’s name is SoFi (short for soft robotic fish), and according to its creators at MIT’s computer science and AI lab CSAIL, it’s the most versatile bot of its kind. And with its built-in cameras, scientists should be able to use SoFi to get close to the ocean’s inhabitants without spooking them — hopefully giving us greater insight into the lives of under-observed sea creatures.

SoFi is not the first robot fish designed for scientific use, but it does bring together a number of different innovations that give it a unique advantage.

“It’s elegant and beautiful to watch in motion.”

For a start, its housing is made from molded and 3D printed plastics, meaning it’s cheap and fast to fabricate. It’s got a built-in buoyancy tank full of compressed air that means it can adjust its depth and linger at specific points in the water column (good for stakeouts). It’s also got a custom control system, which uses coded audio bursts to transmit instructions from a human operator. SoFi can swim semi-autonomously, and will keep going in a specific direction without oversight, but a handler can steer it left or right, up and down, using a modified SNES controller.

Most important, though, is SoFi’s propulsion system. This is a powerful hydraulic actuator that pumps water in and out of a pair of internal chambers, moving its tail fin back and forth. Not only is this quieter than using propellors like a submarine, but it’s also less dangerous, as there are no sharp moving parts, and better camouflage. A hydraulic tail is quiet and looks just like the real thing. (Or should that be the real fin.)

According to a paper describing SoFi published in the journal Science Robotics today, the result is a robot fish that blends in, unnoticed, among the underwater crowds. “It’s elegant and beautiful to watch in motion,” CSAIL’s Daniela Rus, a co-author of the paper, tells The Verge. “We were exited to see that our fish could swim side by side with real fish, and they didn’t swim away. This is quite different to when a human diver approaches.”

This sort of robot design — mimicking the shape and movements of real animals — is known as biomimetics. It’s an approach that’s created colonoscopy robots that wriggle like worms, cockroach bots that could scurry alongside search-and-rescue missions, and a variety of seafaring creations taking inspiration in everything from sea turtles to jellyfish.

But, says Rus, compared to earlier biomimetic fish, SoFi is a finished product. “It could be an extraordinary tool for studying marine biology,” she says. “To find out about the secret lives of animals that live underwater, we need to collect more data. This could help.”

Rus and her colleagues are already planning upgrades for SoFi, which could include live-streaming video. (At this point in time, a human operator has to be in line-of-sight with the robot to control it.) Another next step might even involve creating whole schools of robot fish that can navigate as a single creature to collect greater amounts of data; or split off to comb the seafloor as individual scouts. “There are just so many mysterious underwater phenomena we have yet to witness,” says Rus.