Chromodoris (Chromodoris sp.) クロシオイロウミウシ
There are many similar species of Chromadoris to this one. I could not find a match. I am sure that there is a lot of individual variation and many have not been named. I should have taken pictures from more angles. That may have helped a little. Amami 2026
A closer look at the Chromodoris. Amami 2026