Since what was left from the ship was opaque, are you sure that they didn't molt? I thought mine were dead the first time I found a molt. I hope that's the case with yours - keep looking around - they tend to hide right after a molt.
55 gal. reef. Coralife lunar lights 4 x 65, 120 lbs live rock. Remora skimmer, 3 power heads. 2 tank raise false percula,2 pajama cardinal,hermits, snails, Xenia, leathers, mushrooms, polyp frags, yellow sea cucumber, And last but not least - the miserable mantis.