If you want to find the squid to get the stamp you're gonna have to go to the ice berg first and then go play aqua grabber.
Once you're at the Aqua Grabber Game go to the Clam Waters section and find the one that says "Find the main Treasure" and then click start game.
Then if you're lucky you might see the squid at the area on the image below. If you don't see it, then you have to keep playing clam waters until you can. It should come anytime if you keep playing. Good Luck!