I'm gonna say beginner ? I wouldnt call myself an advanced keeper, for years i worked with reptiles, and had a couple betta's lol, only the last year or so have i really down sized my reptile collection amd moved into Fish, Started with my turtle's and Caiman, over the year's there tanks needed something new so i ventured into housing suitable "fish friends" to make the larger tanks more interesting to look at,
I alwasy research before venturing into a new pet and the more i researched various fish species the more tanks popped up around my house lol. I would say i'm far from a beginner, i have dozens of species now, even more fish then reptiles, but still to new to the fish game to call myself advanced
most definitely cant know every possible thing or method so it kinda rules out expert but at lease my fish havent died for unknown reasons or at all for years and i might have a few tricks so at lease advanced