In Central California this is often the most common sea slug around, though this impression may be due to the fact that its orange coloration makes it one of the easiest to find.
While the body shape is consistent, there are several color forms associated with age: the smallest often appear pure orange, medium individuals (1-1/2 inches long) are dark brown with white spots and large examples (3 inches) are light orange with distinctive white spots.
This species lives in the eastern Pacific Ocean, from Vancouver, British Columbia, Canada, to Baja California, Mexico. It also lives in Japan. It feeds on bryozoans.
It was neat to experience this a shell-less marine gastropod in the wild.