1) Highly developed sense of smell, which they use to detect food, mates, and predators, and sometimes to find their way home. They do this with special sensory cells located in olfactory sacs on both sides of the head. Each sac opens to the outside through one or two openings, the nostrils, or nares.
2) Taste buds located in the mouth and on the lips, fins, skin, and barbels (whisker-like organs near the mouth of many bottom feeders).
3) Fish eyes focus by moving farther away or closer to the subject.
4) The lateral line enables fish to detect vibrations in the water, it consists of a system of small canals that run along the head and body. The canals lie in the skin and in the bone or cartilage of the head. They are lined with clusters of sensory cells, or neuromasts, that are sensitive to vibration.
5) ampulle of Lorenzini in cartilaginous fishes can detect weak electrical fields. Helps them locate prey and may also help in navigation.