Wooow I love the movement of the fish!
Really satisfying movements, but the controls need to get used to the repeated mashing of the directional keys. Still, it reminds of good old ecco the dolphin in it's megadrive era!
The third form was not as difficult as I feared after reading your warning, but I was a bit too fast and I ended up stuck in a wall! ^^
Good prototype, would love to see it pushed at least a bit further!