Even if you think 90% of what we keep does not live long (which is not true) that doesn't make it ok to keep fish that have even less of a chance to survive in home aquaria. I would say 20% success rate for Moorish Idols sounds kind of on the generous side.
I personally only know one person who kept one over a year on a diet of sponges. I think his lived 3 years. Again, not a success story by any means.
The ones mentioned above that are still around after 12 years would be a success story but that is so rare.
I don't know why people insist on buying these fish
