Gotta love nano tanks; no need for fancy filtration, just keep a bubbler in a bucket of saltwater, rinse the mechanical pad and swap out 25% weekly!
BTW, the Ga AQ uses ten fish lengths as a rule of thumb for the distance their whale sharks need to swim, ten fish lengths for a fat 4†Tang is a 4’ tank, yet I have kept Yellow Tangs in a 3’ long 40-gallon for a decade
oh yeah, I kept a Banded Coral Shrimp in a Betta bowl for a year with 50% water weekly changes from the 120 predator tank