Why lapu-lapu killed by fishermen?

Actually Lapu-Lapu being killed by a fisherman is just an old Filipino joke. Lapu-Lapu besides the hero of Mactan is also a specie of a fish. That's why when someone asks who killed Lapu-Lapu, the answer would be fisherman or a cook as they were pertaining to the fish and not Lapu-Lapu the hero itself.