On the other hand, when low-frequency electric fields are generated by external sources instead of the fish itself, a different class of electroreceptor organs is used for this passive electrolocation, called ampullary organs.
Ampullae of Lorenzini, special sensing organs, forming a network of jelly-filled canals in cartilaginous fishes
:*Ampullae of Lorenzini respond to electric fields, salinity, and to temperature, but function primarily as electroreceptors