The present invention provides an apparatus having an injurious curved knife for ripping a fishs mouth, to rip a mouth of carnivorous fish using an injurious curved knife having a blade therein, so as to remove the aggression of the carnivorous fish and to derive the carnivorous fish to be killed by other animals so as to protect native herbivorous fish and help the consumption of green algae. According to the present invention, the injurious curve knife is manufactured by bending a steel or stainless steel rod to be inserted into the mouth of the carnivorous fish, pressing, hammering, and grinding an inner side of the rod to make an acute tip and a sharp blade, and coating the tip and the blade to maintain an original state for a long time. The injurious curved knife having a fish-shaped lure with a bag to receive pieces of a live bait and having the blade in the inside is seesaw-connected with a seesaw stripe with respect to a hook of a fishing gut side, and lures the carnivorous fish, so the mouth of the carnivorous fish is ripped when the carnivorous fish bites the lure, and thereby aggression of the carnivorous fish is lost. The lure and the hook in the inside are seesaw-connected with the seesaw stripe with respect to the hook of the fishing gut side, and the injurious curved knife having the blade inside is seesaw-connected triply to the hook of a fishing gut side with a triple seesaw stripe with respect to the hook of a lure side and lures the carnivorous fish, so a body of the carnivorous fish is injured by the injurious curved knife when the carnivorous fish attacks a fish hung to the hook, and thereby the carnivorous fish is killed by other animals. Since the mouth of the carnivorous fish is ripped by the injurious curved knife having the blade inside, the aggression of the carnivorous fish is removed and the number of the carnivorous fish is reduced due to inducement of kill by other animal. Thus, the native herbivorous fish are protected, so the green a
