Mb, did you see where this worm (the linked) comes from? Faulkland Islands, South Sandwich Islands, South Shetland Islands, South Georgia--this thing is from cold waters, freakin' Antarctic waters! BRRRRRR!!! (Can you see my goosebumps?)
Anyway, I doubt you've got an Antarctic critter living in your tank. In the pic all I can see is darkness in the middle, maybe you can tweak it a bit, bump up the gamma maybe? You could also try baiting it with a bit of fish or some such plugged out where it can be more easily photographed.