I drew the stitches for the second layer on a piece of paper you use for making clothes. I secured it on the fabric with a piece of thread.
I made the stitches through the paper.
Then I had to tear the paper careful and remove it. I used a pair of tweezers for it.
I used long and short stitches for the head, a French knot for the eye and satin stitches for the bubbles. It’s not finished yet, I have to do the fin and the tail of my fish.
Update: you can see the finished fish here.