Yeah, I still can not find my Six Line Wrasse at night. Every night he is gone, sleeping somewhere. I am not worried as I see him swimming happily during the day light hours. I knew of the Mucous thing before I bought mine, but it was freaky seeing it for the first time. I saw it when I was moving him to a different tank. I was setting up the tank and had him in a plastic tub covered with a blanket until I was done transferring everything over to the bigger tank. He was in cased in it, lol.
When I first got mine, I thought he had ICK, because of the sand that would stick too him, and the little white spot that is on their tails. I know better now, still freaked me out.
Yes Six Line Wrasse can Burrow, that's why I think I can't find mine, I don't think he sleeps in the rock work, but burrows himself under the rock and sand at night. Still a very cool fish to have and very active and pretty. When they get big they are really impressive looking. I saw a 7 year old one in a reef tank, and I can't wait for mine to get that big! I hope I can keep mine alive for that long!
Fish Sticks, the best thing you can do with your dead fish.