Step #1
Start the work by drawing an oval and a line in the center of the body. Also draw outline fortail.
Step #2
Make outline for face.
Step #3
Make eye & lines just below eye as shown.
Step #4
Draw outline for body & fins.
Step #5
Make tail.
Step #6
Draw lines all over the fish's body as shown.
Step #7
Finally, make necessary improvements to finish.