expression, godan verb (-ru)
General expression for catching fish with a rod and line.
週末に川へ魚を釣りに行く。
I go fishing in the river on weekends.
The verb alone means 'to fish' or 'to lure'; 魚を釣る explicitly includes the object 'fish'.
Phrase composed of 魚 (fish) + を (object marker) + 釣る (to fish).