hiya erm!
if im not mistaken, new wen growth can be, or is, a lighter shade than the rest of the wen. also, skin sloughing off ( or healing tissue) could also be lighter than the surrounding area. another thought is that his wen is clouding up a bit from the differences in water chemistry between the store and your house. i couldnt help but notice the white edges on his tailfin. thats tailrot. now that he is in uncrowded circumstances, the healing will begin. maybe his wen was affected by the same thing that affected his tail.
either way, just keep an eye on it and let us know if it gets much worse. also, as allways, keep your water params as pristine as possible.
hope this helps