Your Yellow Tang will find many macros deeelicious, but they are quite nutritious, so it's not all bad. I swear it cured mine of the HLLE
it came with.
For a non-Tang snack, you may want to try Halimeda. It's kind of cactusy looking.
I believe your Yellow Tang may also leave Sargassum alone.
These are just a couple, but I believe them to be hardy, and fairly attractive.