Caribbean Thread Sketch

I haven't started any new projects since I finished the conceptual art piece last week, so I thought I'd squeeze in a page for the sketchbook project. I had already gessoed, textured, and painted the background on this canvas and was trying to decide what to do next. I thought I would do a simple thread sketch, but I seem to have a hard time keeping things simple! I began with the central elkhorn coral, which I sketched all in one continuous line with variegated thread. Then I added the brain coral in the foreground and a piece of purple netting for the fan coral. I decided to tint the first two corals using inktense pencils. Because the entire coral is not filled in and the background color is still very visible, I think it helps make it look more realistically underwater; what do you think? Finally, I added in the fish: a school of small silver fish (we saw clouds of these swimming together on St. John), a yellow-tailed snapper, some small purple fish, and an eel. I also decided to stitch in a spiny urchin. I like the piece in general and it was good for practicing thread sketching and learning how to do effects like showing movement, making something look like it's underwater, and making lines radiating out from a central point. I do enjoy these underwater scenes, don't I?