An Etymological Dictionary of the German Language/fangen
fangen, fahen, vb., ‘to catch, seize, fish (an anchor), soften (hides),’ from MidHG. vâhen, vân, OHG. fâhan, ‘to catch, intercept, seize’; the common Teut. vb. — Goth. fâhan, OIc. fá, AS. fôn (for *fôhan from *fõhan; wanting in E.) — has the same meaning. Root fanh (whence fãh, fâh), and by a grammatical change fang (this form is really found only in the partic. and pret., but it has made its way in ModHG. into the pres. also), pre-Teut. pank. With the Teut. cognates some have compared the unnasalised root pak, in Lat. pax, pacem (lit. ‘strengthening’?); akin to the nasalised pango (partic. pactum), with g for c?, Sans. pãça, ‘cord’; the root pak appears without a nasal in Teut. fôg; see HG. fügen. —