That's a good question, I planed to have a nice introductory story, but deadline was eating me alive, I have posted the game just minutes before it ends. long short answer, otters use rocks as tools to open some crustaceans shells while floating backwards. sorry the piranhas weren't so different from the regular fishes, that was actually part of the design though the head was planned to be bigger, it looked bigger when I was drawing it, lol, it just got smaller on the game. those are nice feedback tips that indeed I need to include like the visual indicators you mentioned, thanks for spending time to play it!!