Added underwater environment with corals, fishes and seaweeds. I wrote the fish AI and flocking behaviour so they swim around realistically and also will swim away from the player. Also, you can eat them! They will struggle when you grab them and also if they're out of the water. Eating half of it will cripple them and they won't be able to swim and just sink down.
I also wrote a waving shader for the seaweeds and corals. They will wave around with some randomness but also sway according to a global wave current. Tall seaweeds have dynamic foliage bending added and will slow your progress if you try to swim through them.