Mermay Art Challenge

Mermay Challenge. Initial sketch with some cleaner lines on top. Please could I get some feedback specifically on the anatomy (even fantastically) and perspective, but welcome any other critique too? Pose: She is floating in and endless depth water column, looking up to the surface for her next prey.

I am struggling with ellipses in perspective while doing the 20 bent cylinders exercise. Additionally how can I improve my line quality/ smoothness?