Is there a Favia eating worm ? I had a large and growing Favia and it started to decline for no reason. After a few weeks decided to remove and cut off dead area when I noticed a worm in bedded near the area that was still good .
Sometimes bristle worms when large enough will munch on the corals trying to get food out, however it is all not that common. How long have you had the favia and what are your water parameters?
