Alien cetaceans

I've always felt bad for the intelligent waterbound species that must dot the universe. All those intelligences that had the bad luck to evolve where it is inherently hostile to basically all forms of technology. No way to use fire, an environment corrosive for most forms of metal, so conductive that any form of electrical usage would be seriously tricky. What a trap to be born into. It's the kind of thing I worry about sometimes.

But the other day, I realized something wonderful: hydraulics would work better for them! Their hydraulics would be more like pneumatics are for us: cheap and easy to set up, because the working fluid can vent to the atmosphere. No need for return lines! Except hydraulics are much safer and more powerful than pneumatics. They can handle much higher pressures, and because water/oil doesn't compress, the systems don't store (much) energy when pressurized. Air is a spring, in contrast, and a pressurized pneumatics system has a whole lot of energy coiled up in it. The pressure doesn't immediately drop to zero when they have a leak, it keeps on blasting out in ways that tend to make the problem even worse. Hydraulics pressure vessels crack and make a big mess, pneumatic pressure vessels explode.

Water-bound aliens would have the best of both worlds. The power and safety of hydraulics with the ease and cheapness of pneumatics. I'm not sure how they would get to that level of technology in the first place, of course, but I still felt a genuine sense of relief when I realized this. At least something is better for them!