Step 1: Draw the head first. Draw a rounded triangle with a diagonal curved line on the right side and a small horizontal line near the edge to finish the detail for the mouth.
Step 2: Next, draw in a small loop for the eye, just above the mouth and draw a semi-circle across the bottom. Add a dot in the middle for the pupil.
Step 3: Then draw in the side fin, making it hour glass shaped with a few small diagonal lines at the bottom.
Step 4: Draw the body next, making two long curves roughly parallel to each other.
Step 5: Next you'll add in the top and bottom fins. Draw a rounded triangular fin on the top with a few curving lines and add in two similar fins one the bottom, one smaller one just below the top fin and another about the same size closer to the tail.
Step 6: Finally, you'll draw in the vertical tail by drawing two diagonal lines extending up and to the left and down and to the left. Connect the two line with a wavy vertical line and then add in a few curved short lines along the edge.
How to Draw a Cartoon Trout – Step-by-Step Tutorial