The paper fish is done like this:
Fold out an expanded version of the basic form of "catamaran".
1. Fold the corners at the top, and lower them at the bottom.
2. Turn the corner inside out by opening the figure.
3. Fold the side pieces diagonally.
4. Open the bottom corner and flatten it.
5. Lower the angle by wrapping the lower part to the other side of the work.
6. Bend the side pieces, pulling the paper from the bottom corners.
7. Return the corners to their original position.
8. Bend the right corner by pulling the paper up. Turn over.
9. Make a crease.
10. Bend the corner.
11. Open and flatten the "pocket".
12. Lower the corner, opening the eye to the fish.
13. The paper fish is ready.