Green Mushroom coral

Question
QUESTION: Hi, I have a reef aquarium which has been set up for around 18 months with few problems. I have a number of green mushroom corals that have spread through the tank increasing in number from 5 to about 20. However suddenly in the last week all of them have shriveled up and turned brown for no apparent reason. I have a number of fish including 2 clowns, 2 chromis, 1 long nose hawk fish and a 6 line wrasse. My tank is now looking bare as the mushrooms were very big and well distributed, how could this have happened and what can I do to fix it?

Thanks

ANSWER: Hi Alex. Have you checked your water quality recently and what is it testing at? When was the last time you did a partial water change? How old are your bulbs or did you change them recently and could anything have entered your tank that could be toxic to the corals? Have you changed brands of salt mix? Have you used different water then you usually do for your top offs or partial? Have you added anything at all to the tank recently? Have you noticed if the hawkfish has been perching on the mushrooms more than he should lately?
Mushrooms not getting enough light or too much light will often turn brown in color. There is also a condition in mushrooms that is unexplained. Mushrooms that have been in a tank suddenly start to shrivel up and turn color. Even though water quality and lighting has remained good there seems to be nothing that can snap them out of it. Sometimes only some mushrooms are effected and sometimes the whole colony can be effected. No amount of water changes or additives seem to have an effect on them and there doesn't seem to be a reason for the wasting away of these polyps. Suddenly they may all recover though this is rare. Most of the time they fail to thrive for no apparent reason and it just makes us more aware that there is still so much we don't know about these corals. There is virtually nothing known about the disease or physiology of these mushrooms and what could be a relatively simple explanation is still a puzzle. Check your lighting. Bulbs should be changed every 6 months to a year. If they start to get worn out the mushrooms may not be getting an adequate amount of light. If you recently upgraded your lights then they may be getting too much light. While mushrooms need good lighting to survive they will often not do well under too intense of lighting either. They require a slow current and do not like to be tread on by hermit crabs or shrimp.  In short check your lighting and change your bulbs if needed. Check your water quality and make any adjustments if needed. keep them as well fed as you have been and hope that they will snap out of it. Other then that there really is not much you can do.

---------- FOLLOW-UP ----------

QUESTION: Hi Jennifer,

Thanks for the reply, to answer your questions, I do water quality checks regularly and have not had any problems, a few months ago the Nitrate suddenly got very high and I lost a magnifica but I have since fixed this and the water has been good since.  I do regular water changes (generally once every one or two weeks)and get my water from the same place every time, the bulbs have been in the tank for about 9 to 12 months and were doing very well, the Hawk fish has never used the mushrooms to perch on he prefers one on the powerheads and a tree coral I have. I have added a new soft coral about 3 months ago which I was told would sting other corals if it touched them, but it is no where near the mushrooms and has been in there for some time.

I have not changed the light for about 12 or 14 months so will try that, also what is the best type of food for this type of coral?

Thanks

Answer
Hello again Alex. You may just be looking at a lighting issue here. Although mushrooms do not require intense lighting they still do contain zooxanthellate in their tissues which require some reef lighting. Bulbs tend to lose much of their intensity over time and usually by the time they are a year old no longer have the same spectrum wavelengths to support most corals well. Due to the fact that mushrooms will survive under lower light levels, they must require large amounts of food for survival. Usually if you are feeding a frozen meaty marine food too your fish simply adding the water it is thawed out in is enough. Sometimes this may not be enough if you have allot of corals or filter feeding inverts in your tank and you may have to supplement their diet by target feeding them. Any small plankton coral food will do. I also like to use a food supplement called selcon to my thawing food to boost the nutrition for my fish and to boost the nutrition of the left over juices from the food. You can target feed your mushrooms simply by squirt the juices or coral food over the mushrooms with a syringe or turkey baster. Once a week is usually all it takes.