New robots bring new tricks. Robots that emulate fish are more effective than robots that are using propellers. If the robot has similar fins and tails with fish. It won't get stuck to the algae and water vegetables so easily as propellers using robots. The problem with small-size robots is that they have limited power sources. The thing is that also larger nuclear-powered submarines can have fins and structures like pike fish that kind of submarine might have stealth drive along with propellers. Structures that are used and tested in miniature submarines. Can turn to use in larger-scale submarines. There is also tested the cuttlefish-looking submarine construction. Those kinds of systems can use water jets for driving fast underwater. Then the robot can use those fins in the area where the system needs to operate accurately. Those robots can be of various sizes. And they can use to recover the material from the bottom of the oceans by using manipulator's arms....