This is why I keep all my magazines! I remember using magazines multiple times for school projects! But this-Really cool idea - cardboard doll house with magazine pictures. Could do with a firehouse/something more boyish, too.
Make the fish out of cardboard or felt, and thread it to the button. For the aquarium, you just need a box. Remove all 8 flaps, then cut windows in the sides and slots for the fish in the top with a box cutter or exacto knife.