Propeller-powered underwater vehicles have long helped scientists explore aquatic environments, Robohub notes, but spinning blades can snag on vegetation, stir up sediment and startle wildlife.
That makes them poorly suited to shallow creeks and dense weeds. EPFL's scalable robot ScaFi is a robotic fish whose swimming ability holds up at small, medium and large sizes.
Source: robohub.org, reported 09-28. https://robohub.org/small-medium-or-large-a-robotic-fish-maintains-its-swimming-ability/