An Etymological Dictionary of the German Language/Aalraupe
Aalraupe, f., ‘eel-pout' (also called Aalquappe, see Quappe), an eel-like fish, originally called Raupe merely; in MidHG. rū̆ppe, OHG. rûppa; as the MidHG. rutte (the equivalent and parallel form) indicates, the base of the word is probably supplied by the Lat. rubêta, from which, through the Teut. custom of displacing the accent in borrowed words (see Abt), we get rúbeta, and then, by the assimilation of the consonants through syncope of the intermediate e, the forms mentioned; names of fishes borrowed in OHG. from Lat. rarely occur. See Quappe.