How I use Panorama and Primitive in Clip Studio Paint to create an aquatic illustration. What are Primitive you ask? They are geometric shapes use in 3d modeling, animation and sculpting software

An Underwater Panorama scene

3d models of sea life

I use a Primitive plane in my first row of sea weed that you see in the light green

I use more Primitives planes that you see in the dark green and blues for more sea weed and corals