I have a beautiful Half moon named Myr that for the life of my don't know what to call his colour, it dosen't photo well, but his fins run through an oil slick like colouring as he swims. he is pastel Blue in body and on the edge of fins, when I got him he was almost slate grey. I thought he might be a marble but other than the first bit of "thank goodness I am out of that cup" darkening he hasn't changed colour. if anyone has an idea what to call it, I would LOVE to know. here are some pics:
sorry about the links, I just can't seem to get the coding for pics.