voxmode

good morning and wan to check with the experts out there ... all the corals (cynarinas, fox, octos, elegance, hammers) in my tank are healthy and opening well. EXCEPT for four of the brains whcih never open at all. A careful watch reveals that two of my regal (blue) tangs are nibbling on the brains which speaks why they never open up at all. Is it common for blue tangs to nibble at corals? my other tangs incl sailfin, purple, yellow - do they pose as a hazard as well? other fishes inside incl pair of maroon clowns hosted by a rose anemone and few cardinals ... any comments and suggestions are most welcome and thanking you in advance for your kind feedbacks. a newbie,