How can you get a baby squid in happy aquarium?

Well, first one of your friends has to find one. If they find one and then publish it to their page, when you see it in the bottom right hand corner there will be a button that says "adopt the squid!" When you see it, click on it. It will then take you to your Happy Aquarium page and should say something like, "YaY! You gave the Squid a home!" or, if someone has beaten you to it, (sorry) but it will tell you that it has already been adopted. :D