I have swam with these beauties 7 or 8 times in Hawaii (where they are the most common fish) and French Polynesia where they are also very common but not as much as Hawaii.
In much of Hawaii the reefs are bare and algae takes over much of it. It kind of looks like a gray, half dead algae but the Idols feast on this stuff as no other fish does.
In the rest of the South Pacific I have followed them many times and the reefs are much better there so Idols have other friends for company. There the Idols eat mostly a lime green sponge that I can't identify. As a matter of fact, that is all I saw them eat there. The male (I think) seems to find this sponge first and starts to eat it, then a few minutes later the "female" catches up to him and she eats while he goes off on another 100 yard circle of the reef looking for sponge.
I located a sponge in New York that grows on floating wooden docks at the surface and it is very easy to collect. It looks like giant human ears and is the same color. Like a light tan.
My last idol who lived almost 5 years would almost jump out of the water for it. I would collect it and freeze it as I couldn't keep it alive for more than a few days.
4FordFamily is correct, their metabolism must work very lousy and I believe that is because their food contains almost no nutrition which is why nothing else eats it.
I built a feeder which was a dish that sat on the bottom. There was a tube that went to the surface with a small funnel on top of it. Above that was an auto feeder which woud deposit fish oil soaked pellets into the funnel 6 or 7 times a day. A tiny bit of water was also pumped into the funnel and the pellets would go down into the dish where the Idol would wait for them. On every pass around the tank, he would inspect the dish.
His other meal was that sponge, clams, live worms and frozen banana. (yeah, I know!).
But after 5 years he just didn't seem to want to live any more and died which happens to many of them and we don't know why. My tank which is a 6' long 100 gallon tank seemed much to small for him so I may get another one soon as I am moving and will get a larger tank. I first have to see if I can collect that sponge in my new marina.
Now I "think" I can keep one. But if i don't keep it for at least 10 years, I will consider it a failure because if any fish dies before it's presumed lifespan, I consider it a failure.
This was Hawaii
This was Bora Bora in Tahiti,
