Algae Death

Question
6 months ago I purchased a 90 gallon tank off of a friend of mine. He had that tank up and running for 6 years. I came home from short vacation and when I came home it looked like most of my algae seems to be dying. And once where there was a lot of hair algae about 3 inches long has disappeared. Also my mushroom frag was dead. I had someone feed my fish while I was gone and all the rest of my coral and fish are doing well. I'm stumped. I think maybe my rabbit fish ate the coral because his feedings were cut back some. I did move the mushroom frag recently and maybe it didn't like it there. I also added a protein skimmer about 4 weeks ago. I'm just not sure.  

Answer
Hi Michael. I am not sure exactly what has happened to your algae but the chances are that if the feedings were cut back due to you being away then your rabbit fish, who is mostly herbivore, got hungry and started munching on the algae. Also if you cut back the feeding by quite a bit the possibility of you decreasing the amount of waste output is good. Algae gather nutrients from these waste products in order to grow. The combination of a hungry rabbit fish and less nutrients in the water will do the trick in eliminating hair algae. This is not necessarily a bad thing! I get questions all the time from people wanting to get rid of their hair algae. If all your water levels are checking out good and you have not noticed any problems with any of your fish and corals then I would say this is not so much a cause for concern. I think you are right about the mushroom frag. If you recently moved it and then went away on vacation for a little while the chances are that you weren't there to observe weather the coral was happy in its new location or not. It may have not liked the new spot. Also be careful when moving any coral, make sure you do not move them too close to another coral that may have a detrimental effect on the health of both corals. Corals use a kind of chemical warfare in order to compete for space on the reef. In a tank these chemicals that are released can be quite toxic to one another. Be sure you didn't move the mushroom too close to a more toxic coral because that would cause a slow demise and decay over a period of a few days or so. Other than the explanations I have given you I do not know for sure what happened. As long as everything else seems okay and your tank water is checking out fine you may just have to chalk it up to one of those unknown events. You weren't there to witness this happening and you may never really know what happened!