I'm not sure what it was... And i probably will never know. I added antibacterial remedy to the tank [mega-lx or something] along with fungal remover. It might of been scrapes or something else. The day after I discovered the blotches I made sure all of the possible things were changed. I moved around all live rock so that none of the sharper ends were open to shark, created more hiding spaces for the shark [basiclly remodeled the tank], added more sand in places that were relatively shallower in sand than other [there was originally crushed coral there] ,and performed 25% water change. Everything is going along well now and shark is eating, but something disturbing happened on sunday... it did a side roll. I wasn't completely sure what was happening but i added another dose of antibacterial remedy.