While a fish might seem to have an exclusive diet, they’ll often chow down on “off-menu” offerings, as wellCarnivorous fish eat meat, herbivorous fish eat algae/plants, and omnivorous fish eat both. That’s the order of things, and any fish we buy for our aquariums should fit nicely into one of these categories so we know exactly what to feed it, right? Well, if that’s the case, why on earth do my blue-chin triggers (Xanthichthys auromarginatus)—carnivores by nature—always beat my tangs and foxface to the dried algae sheets I offer and actually eat the lion’s share? After all, FishBase describes X. auromarginatus as “[forming] loose aggregations a few meters above the bottom where it feeds on zooplankton, particularly copepods.” Nowhere in this statement do you see, “Oh yeah, and it likes to tear into algae from time to time, too!”On the flipside of the coin, just as my triggers seem to enjoy ordering “off-menu,” my herbivorous yellow tang (Zebrasoma flavescens), Atlantic blue tang (Acanthurus coeruleus), and one-spot foxface (Siganus unimaculatus) will greedily gobble up any meaty items that they can fit in their mouths as well. What gives? MORE