Sea side with manta rays

Sea side with manta rays - student project

Thanks for this class, I learned a lot. Especially about blending the colors and how to draw the waves.

I’m not quite happy with the manta rays. I struggled to draw them properly under the surface of the water. I removed some parts of the animals with a mask, used gaussian blur and transparency. 

How would you draw animals under the ocean surface? I’m looking forward to some tips

Sea side with manta rays - image 1 - student project