I have a piece of large 'Green Mushroom Rock' which I believe looks very much like a Ricordea. It has been in my tank for over a year and thrived. However, I have noticed that over the last couple of days, one of the mushrooms has developed a number of brown patches on its skin.
Does anyone have any idea what could have caused this and what I should do?
your magnesium and calcium is alittle low. also do you have a KH reading? your mushroom poylp should be fine as they are very hardy. my advice would be to monitor it closely for now to see if it deteriorates or improves. is it a variety that has zooxanthellate or not? if it doesn't then you can see if it excepts some meaty foods maybe? i have two mushroom polyps that are very hungry. ive watched the largest one eat a whole prawn before!!