Step 5: Inside the head, near the top, draw a circle for the piranha's eye. Make the circle a bit wavy to indicate the eye's soft edge. Inside the eye, draw a small circle for the pupil. Shade in the circle. Draw a few lines around the fish's pupil to for extra detail.
Step 6: On the tip of the head, draw the piranha's open mouth using a couple of lines. The shape of the mouth should be similar to a greater- than sign (>). Add a few lines under the mouth for the lower lip.
Step 7: Inside the mouth, on the top and bottom edges, draw a series of triangle-like shapes for the teeth. The piranha's teeth basically consist of a zigzag line along the edge of the mouth. Add a few more triangle-like spikes between the first set of teeth for the teeth on the other side of the mouth. Add the top row of teeth the same way. Draw a zigzag line along the top of the mouth.
Step 8: Draw the piranha's dorsal fin at the top of the body by first drawing a curved diagonal line. Then draw a wavy line that's similar to the letter S on the right side to complete the dorsal fin.
Step 9: Inside the main circle, near the bottom, draw a curved horizontal line for the top part of the piranha's pectoral fin. The bottom part of the fin is made up of a long line that is angled near the left side. Make the lower, right edge of the fin a bit jagged. Add a couple of curved lines on the left side for the base.