zemuro- its not phytoplankton, its just plain "plankton" (phytoplanktons are plants)
a few trigger species are considered planktonic feeding and are identified up their upturned mouths. Nigers, blue cheeks, pinktailed, crosshatch, sargassum as the ones most often associated w/ this. these guys tend to be more predictable and somewhat reefsafe, and will frequently leave your hermits and snails alone.
Any trigger that has a forward facing mouth(like a huma or clown trigger) can pretty much munch on anything.
A w/ all triggers each one has its own personality and one persons mellow trigger will be another persons nightmare