Step 6: Draw a similar triangle-like shape at the bottom as a guide for the Moorish idol's anal fin. This guide should be closer to the right in comparison to the dorsal fin at the top.
Step 7: On the right side of the circle, draw the guide for the Moorish idol's tail or caudal fin using a series of lines. This guide is formed by three lines. Pay attention to its size in relation to the main circle and the fish's other fins.
That's it for the guides! From this point on, press harder with your pencil for a more defined drawing.
Step 8: Lightly sketch a small circle near the left edge of the head for the eye. Use the construction lines as guides for placement. When you get the size and position right, darken the eye. Add a few curved lines around the Moorish idol's eye for extra detail. Notice how small the eye and surrounding detail are in relation to the rest of the fish's body.
Step 9: Use the small arc on the right as a guide to draw the top part of the Moorish idol's mouth. Follow the basic path of the guide as you draw the shape but make it slightly curvier. Curve the line in toward the inside of the arc to create the fish's mouth opening.