Doesn't grow fast, but does come back. Cyano package from GARF had no discernable impact. Here's a quick list of my experiences with herbivores. Problems arise when the herbivores aren't clear on the concept that they're supposed to be eating algae, not frozen zooplankton, or when they up 'n die. Small Herbivorous Hermits Very Hair, Cyano Need extra shells.
Blue legs stay small, Scarlet legs get a little larger.
Dragon Gobies Fair Hair Hardy after acclimation when completely unhassled by other fish. Very easily cowed into starvation. Zebrasoma Tangs Fair Hair Hardy with well-oxygenated water and cleaner shrimp. I've had fairly bad luck with these tangs, but lots of others report success. These tangs don't tend to eat most prepared foods, I'm not even sure if they'll eat green nori.