So, I just got a neat idea for an aquamarine species, how they look, what kind of technology they have, and a rough outline of their society/culture. But there is one glaring issue, they started out underwater. To be more specific, the stone age. We humans, as primates, had major developments by learning how to use objects as tools, like wielding a stick, poking something with it, or discovering fire. Such things brought us onto the path to where we are today. Doing the same underwater, is much more difficult. Discovering fire would be virtually impossible. Using tools is also severely limited, not impossible I guess, but I don't see how they could reach a stage, in which they build underwater power plants for electricity, or inventing combustion engines, not to mention a space craft, without leaving the water. The 'leaving the water' part I already solved, but the time before that, basically their stone age, I haven't fully solved yet. The problem is: Intelligence! It doesn't come out of nowhere. We humans made big leaps in intelligence by discovering things, like learning to use objects as tools. This enabled us to become more intelligent and start to invent more advanced tools. The reason: environmental dangers, like predators, wind & weather, temperatures, natural disasters, and so on. The question is, how could this translate to an underwater species? I have chosen squids and octopi as rough basis for the species, but how would they use tools to invent things underwater? What could be there, underwater, for them to become more intelligent, and thus stepping on a similar path as we did? Or have I reached a point of impossibility? A point, where it's just too far fetched?