What is an "advanced aquarist" ??

[Delphinus]

I like the definition of advanced means you're pushing the boundaries of knowledge and then contributing that knowledge in some meaningful fashion.

Anything beyond "newby" is simply someone who's had experience enough in something to be able to mentor someone else on that topic. This would be "intermediate" in my view because you can't know everything about everything, so you're always still learning. That puts most of us squarely in the intermediate stage, and most of us will probably stay there.

"Expert" on the other hand is a term I don't like either. I'm leery and skeptical of anyone who claims themselves an expert at anything.

Another point though is a lot of vendors will put caveats on their livestock notes "for advanced aquarists" because it is a species with notoriety for being poor survivors in captivity. Ie., a store might claim a Moorish Idol is for "advanced aquarists only" because it would be a poor choice for someone new to the hobby - the outcome is likely heartbreak. So the caveat is there so that people try to enter into things with both eyes open.