Paper Plate Aquarium Porthole. You have so many options with this you could use fish stickers, crackers, or make your own with paper. Tissue paper for seaweed or color beads and more to create their home.
Australian artist Helle Jorgenson is beyond amazing! Barnacles made out of reclaimed wool, and discarded plastic beautifully crafted into sea anemones… Pure awesomeness! Check out her other work via the link.