The only thing I see is the fishes natural lateral line, which runs from the head to the tail. It consists of a bunch of tubular canals which run under the skin which are all linked together. The tubes go from the skin surface to sensory organs with nerve endings which then send signals to the fish's brain. This system enables the fish to "feel" or sense pressure, temperature, and changes in water movement. The water movement is felt as vibrations, these vibrations cause a sensation which can alert the fish to approaching fish or to aid in sensing what they can not see, such as predation for other fish.