You probably know what fish tastes like, but do you know how fish taste? Like all vertebrates, fish have five senses, including a sense of taste. And it’s probably more powerful than yours.
For fish, taste isn’t limited to the tongue. Fish have taste buds not just on their tongues, but on their lips and bodies, too. Taste buds need moisture to work (try eating with a dry mouth), and because fish are surrounded by water all the time, taste buds can survive on the exterior skin of their flanks and fins as well as inside their mouths.
Being able to taste with their bodies helps fish find food. Instead of smelling dinner nearby, they can taste it, long before the meal gets anywhere near their mouth. Bottom-feeders like catfish are especially keen tasters, which helps them locate edible morsels in muddy, dark waters. The channel catfish has around 680,000 taste buds [PDF] all over its body, including on its whisker-like barbels. That’s an especially high number of taste buds compared to most other animals (humans have about 5,000 in their mouths).
Having taste buds outside the body may help fish know what to eat when they can’t smell (fish have nostrils and pick up chemical cues similar to the way we would smell—minus the air, of course). A study of another scavenger called the deep-sea grenadier concluded that the fish’s sniffer became ineffective at close ranges, leading the fish to poke around with their barbels instead.
It’s kind of like having taste buds at the end of your fingertips.