Devil's Advocate

I try to make species in my large sci-fi universe have a context that informs genetic adaptation, technology, cultural practices, etc. I just have the hardest time with waterborne species. Human development is assumed to be almost completely about technological development (fire, printing press, etc.). Oceanic species don't need buildings based on square corners let alone cooking with fire. True waterborne would have a complete 360-degree experience based on open water, temperature, water pressure, tides, major storms, etc. Radically different than our real-world experience.

Do any of you have ideas or resources for developing a true waterborne species?
What would an advanced species be like without a need for the wheel?
What would be the hallmarks instead of the human biped model?
What species-normal special abilities would they have? Sonar?

Think jellyfish, dolphin, squid, and shark, rather than reef dwellers, sea caves or boats. Uplifting water species is not part of this, either. And no mermaids or Atlantis please since these are both biped oriented. So far one of my waterborne has a shark base with biologically possible appendages -- sort of a murky dinosaur.

Thank you for anything.