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SMELL AND TASTE
Catfish have exceptional senses of smell and taste. They can detect molecules of a substance in the water. Because of their similarity, scientists tend to lump both senses together and call it "chemoreception." Chemoreception is critical when finding prey, avoiding predators, locating other catfish, coordinating spawning times, and homing in on residence and spawning sites.
The sense of smell detects from afar, while taste determines if what is eaten is good once bitten. Catfish can actually taste items 15 to 20 feet away without biting. They have more than 175,000 taste buds on their body. Probably the reason many call them "The swimming tongue."
Some catfish can detect concentrations of some substances of one part per million. That would be like dissolving an ounce of something in 100,000 railroad tank cars. The keen sense of smell can guide cats to bait lying hundreds of yards upstream in a muddy river in the middle of the night. Cats decide which direction to swim by comparing how strong the taste receptors on either side of the body is stimulated.
VISION
Catfish have little beady eyes. In spite of that, they have great vision; well except for the blind catfish species in Texas. In Florida's Clermont Chain of Lakes, channel catfish rise up in the water column and feed on transparent invertebrates, the Phantom Midge.
Catfish eyes, like other fish, have six sets of muscles for shifting eye position. The back of the eye has a reflective surface that concentrates and reflects light to aid the vision in dim light.
Experiments on the catfish eye indicate that it can distinguish colors.
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HEARING
Catfish hear with the inner ears, much like man does. The sounds are projected through a series of fluid filled sacs lined with hair-like projections. Each sac contains a bone called an otolith.
To understand the fish's hearing, picture a sound wave. These waves, moving through the water, pass through the fish's body like it wasn't even there. The density of the water and the fish are almost the same. When the sound waves reach the otoliths, they vibrate. The vibrations bend the hair-like projections, and nerves carry the message to the brain. Literally, the fish hears through its side.
Catfish hear better than most other fish. The inner ear is connected to the fish's air bladder. The air bladder amplifies the sound, improving sensitivity and hearing range, a kind of built in stereo system. Catfish can detect very high frequency sounds.
Catfish also detect low frequency sounds with their lateral line. Some of the sensory cells in the inner ear and lateral line are turned in different directions. It helps the fish detect the source of the sound, similar to sonar.
FEEL
North American catfish lack scales--except for the armored catfish species found in southern climates--making them more vulnerable to injury than scaled species.
However, the skin of the catfish offers other advantages like sensitivity for feeling objects like rocks and brush.
Catfish are a sensitive lot. They can taste, smell, hear and feel better than most other North American fishes. It is little wonder anglers are so successful when they use nature's own essences to tempt them to bite.
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