322 stickers.
Build the hall first, then the tanks, then the night. There are more homes for creatures here than in any other kind on the sheet: tanks on stands, round bowls, a touch pool with starfish, tall tanks that each hold one big sea animal, a shark or a turtle. Around them go the ticket desk, the rope barrier, the keeper's cart with its buckets and net, a diver's helmet, a ship in a bottle, a brass porthole, and a thermos of tea for the long shift.
Put a jellyfish tank on the counter and it rides the counter. Move the counter later and the tank comes along. The tanks, the jellyfish lamp and the wall lights are real lights: the room was drawn for the night, and with it on, the whole building is asleep except the water.
Pick the room you build in: the plain hall, or a house with a gallery upstairs to look down into the big tank. Change the walls and the floor to suit the deep blue. Nothing counts and nothing ends; you stop when it is quiet enough to hear the pumps.
