Press the key Space Bar to turn it to night and see the fish sleep. Press the key "F" to feed the fish. (Press keys to find a secret (glitchy fish)). Press they key "Q" to become a fish too. Click the bubbles to make it classic mode. In classic mode the fish might twitch a bit. I added a thing that says fish, but you might not want to click it just see.
I will still add to this. It might just lag a little before the night but it'll get there. The big fish is a little glitched. Credits to my fish for your great looks! (I added a fish mouse). The mouse hides behind the fish too. Report any bugs in the comments please! Also check out my studio (below) the awesome cheese! There is just a little glitch (you'll find it once you see "My Fish Tank 2 Password/Code) ehh so um... just don't do that.