Yesterday morning my LN butterfly seemed fine. Last night my wife said, do you realise that you fish is covered in white spot. Sure enough, tail and fins covered in white spots. Woke up this morning (less then 12 hours later) and it's all gone. He hangs out with my two clowns, and they fan the sand quite alot, so I can't make out if it's sand particles that stick to him, or ich. If ich stays on for longer then 12 hours, then I guess it's sand. He eats like a pig and swims around happily, plus I have two clowns and a gobie and they show no signs of anything?