seaslug id

I noticed this seaslug (nudi? flatworm?) out in the blue, maybe 50 yards from the reef. I only had a wide angle lens, but I took a picture anyways cause it looked so strange. It was moving like a flatwork, but it looked more like a nudibranch. I thought it could perhaps be Sclerodoris trenberthi. Image taken at about 20 feet, Eastern Fields, PNG. It was maybe 2-3 cm. Anyone have an idea?

It's a flatworm, Cor. The translucent body with a network of forking lines & internal organs is similar to ones I've seen labelled as Paraplanocera.