Step #1
Start the work by drawing two ovals & line as shown.
Step #2
Draw outline for fins, mouth & tail. Also draw a line in the middle of the body and a circle.
Step #3
Make head & eye.
Step #4
Draw outline for body.
Step #5
Make tail & fins.
Step #6
Draw retinas, mouth & gill as shown.
Step #7
Make lines over the tail and fins as shown.
Step #8
Make diagonal lines going from left to right as shown.
Step #9
Draw diagonal lines going from right to left as shown.
Step #10
Finally, make necessary improvements to finish.