Step #1
Start the work by drawing an oval & a curve line.
Step #2
Draw outline for body & jaw.
Step #3
Make outline for fins & curve line.
Step #4
Draw further fins & tail.
Step #5
Make retinas & several curve lines over the body.
Step #6
Finally, make necessary improvements to finish.
How to Draw and Color Basculin from Pokemon with ProMarkers [Speed Drawing]