What you need2 paper plates
suitable fish material (paper, foam, plastic)
stapeler or glue
You start painting the inside of one of the plates blue to illustrate the water – you can also put plastic or other “watery materials on it” when the paint is dry you paint – or make the sea weed.
After you paint the back side of the other plate, it can also be decorated with whatever you would find nice. Here it is simply painted since it was very small children as a craft project in a crèche.
After that you staple the two plates together. If you want you can put a piece of see-through plastic in between to simulate the glass in the fish tank but it works fine without it.
You make some fish. Here I made the kids paint a painting on a piece of thick paper from where I cut out fish the size I thought would fit.
I hanged them up in a string so they would move when touched like swimming fish.