Fractional benefit symbiosis refers to the ecological relationship between two species in the biological world. One kind of organism will obtain survival benefits due to this relationship. However, the other organism does not gain any benefits in this relationship, but ialso no harm is gained, just to drive the other party to gain benefits.
According to the above definition, which of the followings belongs to the symbiosis of profit?
Crucian carp's swimming ability is poor, and its dorsal fin evolved into a sucker attached to the shark. As the shark swims around the sea, when the shark catches prey, the carp steals the remaining food.