Observing fish in their natural ocean habitats goes a long way toward understanding their behaviors and interactions with the surrounding environment. But doing so isn't easy. Using underwater vehicles to get a look at these species is one option, but they often come with a slew of limitations. Some are loud and use propellers or jet-propulsion that disturb fish and their surroundings. And many are designed in a way that doesn't allow them to blend in with the marine environment. Controlling such vehicles is also a challenge and in many cases, they have to be tethered to a boat. But researchers at MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) have come up with a potential solution -- a soft robot that can swim on its own underwater.