Here is a really simple idea that looks really effective and uses shells that you may have collected on the beach.
We started with the two paper plates one of which I cut the centre out of the other was left whole and coloured blue for the sea. Little Boo wanted to put some stars in the back ground of hers as well.
Then some fish were decorated for the centre one was tissue paper the other one she decided to colour in and add some more stars (stars were very popular today).
One side of the other plate was coloured and attached to the back was a wrapper that was clear. To make the window you could also use acetate or a clear plastic wallet. Little Boo helped to tape this on.
All that is needed then is to tape the two plates together then you have a wonderful porthole scene. I think that it would of been better with a larger plate and by using some fishing line on the fish so they could all dangle in different places. However, doing it this way has meant Little Boo can do all of it herself.