Rapsters belong to the family of the microphone fish. Why the evolution let the fish from the Doedelsea grow a microphone is so far still unexplained since the fish themselves cannot speak. Also the mode of operation of their microphones is not investigated, it is only safe to say that round belly of the Rapster works like a type of amplifier. Rapsters prefer shallow, flat coastal regions of the Doedelseas. Because of their microphone rising up and out of the water they are easily recognizable. Since the invention of water tanks several Breggel convinced the fish to change their habitat from the Doedelsea into the water tanks and be employed as microphones for music bands. Each music band on planet Gnum possesses nowadays at least one water tank with a Rapster swimming therein. Their function as a microphone at parties seems to please the fish since it was already very often observed that the fish move their tail fins the rhythm of the music.