Thermoreceptors are sensitive nerve endings that perceive changes in temperature. In most bony fish, they are concentrated in the superficial layers of the skin. There is a distinction between receptors that perceive heat and cold. Fish pick up temperature fluctuations in the range of 0.03-0.07 ° C.
Thermoreceptors in the skin of modern bony fishes respond to temperature stimuli with an extremely short latency period and are involved in thermoregulatory behavior until optimal body temperature is reached.