An Etymological Dictionary of the German Language/Annotated/Quappe
Quappe, feminine, ‘eel-pout, tadpole,’ Modern High German only, from Low German in which the Old Low German word quappa occurs (compare Dutch kwab); the latter is primitively allied to Old Prussian gabawo, ‘toad,’ Old Slovenian żaba (from the primary form *gêba), ‘frog.’ The assumption that the word is borrowed from Latin capito is less probable.