This is my 2nd Moorish Idol. The 1st one was great. It ate well/everything, never bothered any of my corals and it even ate aptasia. I sold it along with all of my big fishes. It is 1 fish that I wish that I had kept.
This 2nd one is doing so so. Much like everyone in the Fish Forum has shared. Every fish is a hit and miss. Due to my aptasia outbreak, I was hoping that this 1 would do the same as the first...eat aptasia. I have had this 1 since October. At the beginning, all it ate was sponge on my LR and it wouldn't eat anything that I introduce to the tank. Once the sponges were all gone, it started to nip on any SPS that is red. So, I put gave it "time out" and placed it in my sump. There, it started to eat Nori. It was in the sump for 2+ months and I felt sorry for it so I put it back in the DT last week. As of today, it only eats Nori, but it hasn't touch any of my corals this time around. Hopefully, the eating habit will improve.
Another difference between this and the first Idol is the way it eats. The 1st actually "attack and will bite" its food. This 1 pushes its mouth into the Nori and whatever breaks/floats it will eat that. I had an exchanged with PaulB who has great knowledge about these Idols. Paul has confirmed that this is something that he has also notice about these Idols. Unfortunately, he doesn't have any evidence as to why they do that.