Many Flytrap monsters are named ___trap, with ___ representing some creature. Fishtrap means this plant catches fish in it. It is spawned by fishing, meaning it might be a submerged freshwater carnivorous plant which preys on freshwater fish. However, this name may or may not be literal and may merely be an exaggeration or instance of creative naming. It could also be a plant that simply lives near the water, and thus may grab a hold of a fisherman's bait.