Straight from the University of Kitakyushu in Japan is "Tai-robot-kun," an amazingly authentic-looking robotic fish. Supposed to be a replica of a Japanese sea bream, the 7kg robot can swim in water like a real fish can. The fish's skin, scales, and fins are made of silicon for an exterior which looks impressively real. To be able to swim, the robot uses its tail fin as well as a particular propulsion system.
The very same propulsion system will be used for a robotic Manta ray that is under development in the same institution. The robotic sea bream can be used for underwater exploration in the future, as well as in-depth sea creature studies, because other than the fact that it looks quite real, the motor produces but a faint sound which (hopefully) wouldn't drive biological creatures away.
Is that really a robot?
Oops...I guess it is. No slimy innards here, move along...