Today I Learned

I envisioned it would be something like octopus, because they absolutely fit the bill with tentacles workable as manipulation appendages, and would absolutely have developed technologies if they lived more than a couple years, and raised their young to pass on information.

I suspect they would be capable of observing stuff around them and understanding how it works at least as well as early agrarian societies, since they have proven able to figure out things like opening jar lids (even from the inside!) and escaping their tanks and stuff. So we’d see them creating nets to ranch fish, and I suspect their technology, continuing down that path, would probably be temperature and bioengineering-based, since electricity would be an epic challenge.

But you can create biological solutions to like.. most stuff, if that’s all you’ve got to work with (in fact there’s a whole field called biomimicry that focuses on finding solutions to modern problems in already-existing forms through nature, and the solutions are almost always simple and effective) Selective breeding wouldn’t be fast or anything but it would do. At least until they sort out other stuff. Ocean life already has a huge huge range of features, it would only be a matter of choosing the right starting creature.

As for heat tech, there are natural heat sources like vents, but there are also sources like radiation/radioactive materials. The water does a good job shielding the radioactivity, so they could probably use the heat generated from either source to do basic mechanical work using something like steam engines. Could also be used to transform materials (cooking food, melting soft metals, etc.)