Step 10: Draw the rest of the head using the initial arc as a guide. Darken the lines to form the koi's head and add a dot on top for the nostril.

Step 11: Draw a series of long curved lines on the right side of the head for the koi's gills.

Step 12: Use the shapes at the top and bottom as guides to draw the koi's dorsal and pectoral fins. Follow the basic path of the guide and darken the lines. Draw some lines within the shape for extra detail. Make the lines wavier to indicate motion as you darken the shape of the fish's pectoral fin. Add some lines inside too.

Step 13: Use the triangle-like shapes on the bottom as guides to draw the koi's pelvic and anal fins. Make the outer edges of the shapes wavier as you follow the guides and add some lines inside for detail.

Step 14: Use the remaining shapes and lines as guides to draw the rest of the koi's body and tail. Follow the path of the initial guides as you darken the lines to form the body. Darken the lines for the tail but make the middle portion indent in toward the koi's body. Add some lines inside the shape for the ridges on the tail.