Scientists build a robotic fish to spy on ocean life

A robot fish dubbed SoFi, created by MIT's Computer Science and Artificial Intelligence Laboratory to explore marine environments, swims at Rainbow Reef off Taveuni, Fiji in this August 2015 handout photo. MIT CSAIL/Handout via REUTERS ATTENTION EDITORS - THIS IMAGE WAS PROVIDED BY A THIRD PARTY. NO RESALES. NO ARCHIVE.

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

It's SoFi, the robotic fish.