I have had this piece since ’04 and grew it from 6 â€"œ 70+ polyps. Approx. 1 month ago I took it in to get it fragged. It was cut into aprrox. 8 pieces. The store kept 1 , I kept 4 and sold the rest. Mine have had the tissue recede and is showing skeleton on 3 1 I have moved to another tank. The store’s piece is dying/dead and three people who bought frags have let me know theirs are dying/dead. What could be the culprit?