Kole Tangs eat detritus, which contains minute algae rather than the filamentous algae eaten by other surgeonfish. The Ctenochaetus species, sometimes called the Bristletooth or Combtooth Tangs, have a protrusive pouting mouth brimming with several rows of small flexible brush like teeth. They use their teeth to sift through various types of algae and poop in an aquarium and then use their mouths to vacuum this food in. In a tank full of shrimp eating Triggers, the poop and algae accumulates quickly.
In the Trigger (Aggressive) Tank, I cannot include the traditional tank cleaners, hermit crabs, snails and serpent starfish, because the Triggers would quickly consume them. A big hungry Kole Tang is just the ticket to providing a sanitation service.