Step 15: Darken the triangular line on top of the body and add some lines inside for the dorsal fin. Make the base of the dorsal thinner too. Darken the square-like shape under the flying fish's body and add some lines for the anal fin.
Step 16: Use the remaining lines and shapes as guides to draw the rest of the body. Darken the outer edges of the guides to create the flying fish's body. Don't overlap the fins that are on this side of the body. Use the tilted, V-shaped lines on the far right as guides to draw the caudal fins. Darken the outer edges of the guides and use wavier lines as you darken the right edges.
Step 17: For a cleaner look, erase as much as you can of the initial guide lines. Don't worry about erasing all of the guides. It's okay to leave some behind. Re-draw any final sketch lines you may have accidentally erased.
Final Step: Add some shading to your flying fish drawing for extra detail. Use a dark value across the top part of the body. Vary the pressure on your pencil to get different degrees of tonal value. Use a lighter value to shade the part of the body that's behind the pectoral fin so that the fin appears transparent. Shade the pectoral fins using a very light value. Use a darker value on the top tips. Use diagonal strokes as you shade the pectoral fins. For a more detailed guide on how to shade, check out this tutorial: How to shade.
Use a light value to shade the bottom of the body. Add a shadow at the bottom of the flying fish's body using a medium value to give the figure more dimension and volume. Shade the rest of the fins using a light value. Use a darker value on the tips. Shading can be time-consuming, so be patient and take breaks. It's a good idea to use reference as you draw for a more accurate depiction of a flying fish. Don't forget to pause the video after each step to draw at your own pace.