Take larger piece of paper of 15 x 15cm and do accordion folds of about 1cm.
Now take blue piece of paper measuring 6 x 6 cm and do smaller accordion folds of 0.5-0.7cm.
Now cut out a small blue semi circle and draw some lines with marker on it as extra detail. Cut some eyes for the fish and keep a dot in the middle with marker.
When you have your entire paper fish pieces ready, fold both your body accordion and fish tail accordion in half.
Glue the fish tail accordion closed and then glue onto the back of body, insert fins and then glue body down. Now finally glue eyes and you are done!