Thanks! I originally intended to implement procedural generation for the rocks there, but I couldn't quite figure out how to do it, so I ended up skipping it. As for the fish, I simply couldn't come up with any new concepts; however, there are currently three unique types in the game: the stingray (which stuns), the yellow fish in the balaclava (which deals damage—yes, the game actually has HP), and the rock—which is enriched uranium.