It takes no more than 5 minutes to make this relief paper fish.
You will need two sheets of printer paper (A4 or Letter). One of them is used for the base, the other – for the fins, tail and body. Cut out the parts, then fold the tail and fins (accordion fold). Cut two slits in fish's body: overlap their sides and glue them to make a "dome".
Glue the parts onto a sheet of paper and decorate. Use your imagination! Any technique and material can be great (here's just one idea).