It is doubtful if they taste like food. Some debris found quite often in a trout's stomach comes from the cases of caddis larvae, which are a favorite food. A good trout bait must appeal both to a trout's sense of smell and taste. A fish can sense food by either smelling or tasting the water. The sense of smell in fishes is relatively acute, as has been proved by numerous experiments.
Trout are no exception.
There is a pair of nostrils on either side of the snout of a trout, but these are not used for breathing. Water enters one nostril, then passes over several folds of skin and out the other. It is well known that salmon are keenly aware of various odors, including the odors of a man's hand placed in the water. It is likely that trout have as keen or nearly as keen a sense of smell as do salmon. A fish has nerve endings scattered over most of its body surface and responds to touch stimuli, but its response is often unlike that of man and many other higher animals.