I was just looking up WD, seems the tail of that fish is darker than normal and there seems to be some deformity of the back near the tail.
Whirling Disease is sometimes called "black tail" because of the color change to the tail. I also causes skeletal deformities and from what I can see I am not certain if that is a deformity or if it is an earlier injury. Did you happen to notice how it was swimming?
Barring taking a sample of the skeletal tissue I couldn't say for sure because it doesn't look like the full blown disease. WD does cause black tails and bending of the spine but usually higher up and more pronounced. I would say it is about a 60% chance of having WD but I would have to check the cartilage under a powerful microscope to check for the signs of the parasite itself.