Studies of pulse‐type gymnotiform electric fishes have suggested that electric organ discharge waveforms (EODw) allow individuals to discriminate between conspecific and allospecific signals, but few have approached this experimentally. Here we implement a phase‐locked playback technique for a syntopic species pair, Brachyhypopomus gauderio and Gymnotus omarorum . Both species respond to changes in stimulus waveform with a tra...