A mad scientist decided he wanted a pet and bought a fish. Being that he’s a mad scientist, he can’t just have any normal tank, though. He built a special one where the coral attacks you, the walls close in to crush you, and the water slowly drains out! Beware, the mad scientist will only revive you three times before he gets bored and leaves you dead for good!

You guide the fish with the joystick and navigate through the coral gaps. If you hit the coral while in the left half of the screen the left side of the tank closes in on you. If you hit the coral while in the right half of the screen the right side closes in on you.

http://www.atariage.com/forums/topic/155629-blocked-in/