Laichzeit

This, like most Rammstein songs, is about sex. The protagonist, "Der Fisch," is supposed to represent man's inner desire to reproduce through... sex. We all have this longing, no matter how much we try to hide it by acting "civilized." At the end of the song all the people "Der Fisch" screwed around with don't want him anymore, which shows that it was all senseless and without deep purpose. The point is that deep down we are all animals in a way, and sex isn't something necessarily "noble" at all.