(Gluten-Free Conversion Chart)- Just to be clear here peeps- Gluten free is NOT healthy in the way some people think it is, only that it is tolerable to eat in the case of coeliacs etc. It is still processed food.
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.