They get much bigger and darker after a big meal Mike. Kinda like corals/anemones after a feeding. The one in your pic looks like it haven't eaten in 3-4 days.
I had trouble getting them to leave the jar. Three days later 2 were still in it. Pulled them out with the baster a gently blew them on a rock. Then I noticed eggs in the jar so I am just leaving the jar for a while maybe I will get some lagniappe. That means extra for you non cajuns.