Label a square piece of paper or card stock that is at least 3 inches wide with an "A" in the upper left-hand corner, a "B" in the upper right-hand corner, a "C" in the lower left-hand corner and a "D" in the lower right-hand corner.
Draw or use a cut-out image of a fish to trace an outline on the square piece of paper. Make sure that the nose of the fish touches the middle of the right side.
Cut out sections "D" and "C" that are not part of the fish and tape them together with the flat ends aligned. Then tape the flat side to the right side of the paper. The "B" side should be next to the "A," and the "C" should be next to the "D."
Cut a triangle out of the taped "DC" section. The top of the triangle, the pointed part, should go through the taped "DC" section. Place the cut-out "DC" section on top of the paper above the "A" and tape it in place.
Create a tessellated design by tracing your cut-out on a large sheet of paper. Start with one row then place the cut-out on top of the row so it fits without any gaps or overlaps. Repeat the process with the bottom row, as needed, to fill up the page.