So running with that lake woman idea, I had a bit of time and sketched out her basic design. Hoping to do some iterations in the future, and experiment a bit with different tail shapes, fins, etc. I liked the idea of a flowy, crown-shape on her head, and after spending a worrying amount of time browsing marine plants, I found these BEAUTIFUL GIANT KELPS. I've included a few of the images I was looking at. They have these gorgeous little bead things, and flow really nicely, so I think they'll be perfect for a crown.
Because she lives deep at the bottom of the lake, her skin is extremely pale and very sensitive to light. To incorporate the water symbol, I thought it would be cool to give her some designs on her skin, like white ink tattoos. I couldn't really find any good pale skin reference photos that also had white ink.
Anyway, I'm a little obsessed with kelp now. More updates soon hopefully : )