Carp
late Middle English: from Old French carpe, from late Latin carpa .
wiktionary
From Middle English carpe, from Old French carpe, from Late Latin carpa, from Gothic *𐌺𐌰𐍂𐍀𐌰( *karpa) [1].
From Old Norse karpa(“to boast, brag”) [1], karp(“bragging”); meaning later changed to "find fault with, carp at" due to influence of Latin carpo.
etymonline
carp (n.)
type of freshwater fish, late 14c., from Old French carpe "carp" (13c.) and directly from Vulgar Latin *carpa (source also of Italian carpa, Spanish carpa), from a Germanic source (compare Middle Dutch carpe, Dutch karper, Old High German karpfo, German Karpfen "carp"); possibly the immediate source is Gothic *karpa. A Danube fish (hence the proposed East Germanic origin of its name), introduced in English ponds 14c. Lithuanian karpis, Russian karp are Germanic loan words.
carp (v.)
early 13c., "to talk, speak, tell," from Old Norse karpa "to brag," which is of unknown origin; meaning turned toward "find fault with, complain," particularly without reason or petulantly (late 14c.) probably by influence of Latin carpere "to slander, revile," literally "to pluck" (which is from PIE root *kerp- "to gather, pluck, harvest"). Related: Carped; carping.