it may interest you to know that there exist fish with a “sense” of electricity. in addition to the usual five (and yes, fish can “smell”…i’ve done experiments) they possess the ability to detect slight aberrations in an electrical field of their own creation. these “weakly electric fish” live, obviously, in dark highly conductive waters and set up a 1 volt field around the electroreceptor in their tails (the “weakly” comes from comparison with their better-known counterparts, the electric eel and those ilk who can set up 600v potentials). they can then judge the resistance and conductivity of other sea creatures that enter their field, thus identifying them. the waveform emitted by the electric organ can even be used to communicate with friends. there is a great article about them here.
i bet my goldfish wishes he had a sense of electricity the way that people wish for sixth senses like x-ray vision or telepathy. these intrepid aquatics have one going for them, but to enjoy it they have to live in the gloomy depths.