I think ocean creatures could really help elevate this game above stuff like Minecraft. You could have ambient, small fish, just there for aesthetics (like the underwater equivalent of birds), larger fish, reptiles, amphibians and crustaceans that you could maybe domesticate or hunt (or be hunted by), and hopefully some sort of fishing mechanics. Maybe you could search the seabed for clams or treasure, or spear fish swimming upriver, a la salmon.
Hostile ocean creatures could really help make building submarine structures more challenging, or maybe just to be cool. Like on Kuehok, in the big, murky ocean underneath the floating islands, you could have some sort of sea monsters to gobble up poor players and animals that fall in.
Jep, I think some creatures lurking in the seas, rivers and lakes may enrich the game a lot. It don’t have to be masses of them … may be a crab, a swarm fish and a bigger one
What i would like to see with hostile creatures (and eventually even boats?) is really big creatures like the Kraken of even bigger. It gives me a feel os epicness and how small you are conpared to them (titan?)