Sorry to be so vague and unscientific here but we have a hammer coral that has been extremely happy for over 6 months now, yet all of a sudden it has started to die off from one end, its not discoloured at all its just not displaying full extension and is slowly dissapearing from its skeleton, its appearance is such that it appears to be dissolving, there is a Goniopra nearby but they have been friends for about 5 months now with now agro noted from either party.
Any common sugestions as o what maybe happening here, Water parameters remain unchanged and no shuffling or disturbances in tank, may have been a little remiss in water changes lately but hasnt shown in water testing?