Fish have the same five major senses as you—sight, smell, scent, taste and touch—although they’re a bit different, adapted for use underwater. Fish use their combined input to locate food and to function at peak levels. Your job is t appeal to these senses to trigger fish into biting or striking. Thus you need to understand how they work.

Sight—Fish are typically quite nearsighted compared to people, although they can sense movement at a distance, so you want to be stealthy when sneaking up on them, particularly in clear, shallow water. Because their eyes typically lie on opposite sides of their heads, rather than in the front like people, most fish only have good depth perception in front of them where their fields of vision overlap, rather than to the sides. Those species with eyes more on the tops of their heads, like pike and muskies, tend to feed forward and upward very well, but can’t see anything beneath them. Thus the importance of placing your lures or baits on target where they can see them. In most cases, that’s in front of and perhaps slightly above the fish.

Most fish can see reasonably well in clear water, although some, like catfish, have relatively poor eyesight which they more than make up for in dingy water through their senses of smell and taste and touch. The major gamefish species you’ll likely fish for typically have fair to good night vision, with some, like walleyes, better than others. It has to do with their eye structure; walleyes have a larger number of something called rods which are sensitive to dim light, yet plenty of another item called cones which allow excellent daylight vision.

It’s a misconception that because fish lack eyelids, that they are afraid of bright, sunny conditions. Actually, their eyes adjust just fine to changing light levels. The fact is, small baitfish (forage fish) usually can see well in sunny conditions and find it easier to function as coordinated schools to elude predators. But when light levels are changing, or at night, small forage fish are at a sight disadvantage because their eye structure lacks the same ability to react (rods), which is why dusk and dawn are key fishing periods when big fish actively feed.

Smell—Most fish will outdo you on this one, with catfish being super smellers, and trout and salmon able to detect miniscule amounts of foreign substances in the water, down to several parts per million. Others, less so, but still quite significant. Suffice it to say that water passing in through the nostrils passes over olfactory sensors, and fish can sense whether something is good or bad. Fishermen often disguise their presence by adding a scent product to their lure, using a scented lure to begin with, or relying on livebait.

Taste—Taste is closely related to smell, and is once again important. Fish not only can taste what they’ve put in their mouths, but can sense items in the water passing across taste receptors on their tongues. Catfish even have external whiskers that they use for touch and taste purposes.

Touch—When they touch something, typically with their mouths, fish sense something good, bad or indifferent. You’d logically think a soft lure would be best because it feels lifelike, as opposed to a hard one that feels like something phony. But not necessarily. Fish are continually biting down on smaller fish with sharp spines that stick them in the mouth, yet don’t seem too mind much. For slow-moving, tempting tactics, lifelike lures are probably a good thing. Yet for fast-moving lures that trigger sudden reflex strikes, harder baits often excel.

Sound—Fish have ears; you just can’t see them, because they’re inside their heads. But higher-frequency sound waves do indeed penetrate to ear bones called otoliths that detect external sounds. Because sound travels well in water, and in fact about four times faster than it does in air, fish routinely use it to orient to food opportunities and to sense danger.

We tend to think of the underwater world as being silent and mysterious, but the fact is, fish are bombarded with a cacophony of sounds on a regular basis. Sounds alert fish, good or bad, so try not to bang your feet in the boat and cause sudden unnatural sounds. They become accustomed to regular noises, like the distant running of outboard motors, but when you suddenly start your outboard or drop your thermos on the bottom of the boat, they know something unnatural is nearby, and might even associate it with danger. On the positive side, they can hear your lures or baits approaching, too, right down to the subtle tap, tap, tap of a jig bouncing on and off bottom.

Lateral line—What the heck is a lateral line? Well, if you look closely at the sides of most fish, you’ll likely detect a faint line passing horizontally from head to tail, looking something like an interruption in the scale pattern, or perhaps even a scar. That’s actually their lateral line, which is an organ designed to detect vibration. While their ears tend to pick up high-pitched sounds at a distance, it’s a fish’s lateral line that detects the approach of low-frequency vibrations, such as the throb of your wobbling lure—whomp, whomp, whomp. It alerts the fish to turn toward the approaching intruder and begin trying to decide whether it’s something good to eat, something trying to eat it, or some other danger. Many traditional favorite lure styles produce an attractive vibration resembling food items in nature, which enhances why they work in the first place.

All these senses contribute to how a fish functions underwater. The better you appeal to the fish’s combined abilities to sense your offerings, tailoring them to the individual species you’re after, the more fish you’ll usually catch.