This video is believed to be the first photo documentation of a grouper making an open water kill of an invasive lionfish without encouragement of any kind by a diver. Footage by Jim Hart, co-founder and executive director of Lionfish University.There is some question as to whether the grouper is driving the lionfish out into open water, or whether the lionfish is following the grouper. It's clear to me, that as in most biological questions, the answer is both. The grouper is clearly showing a gustatory interest in the lionfish, but the lionfish is responding by pointing its poisonous spines at the grouper and advancing, in and attempt to intimidate and drive off the grouper. This brings the lionfish out of cover, and enables the grouper to suddenly strike, stun and eat the lionfish, hopefully without getting stung, although I don't know how severe the toxin would be to another fish. Enough to be discouraging, certainly.
This grouper clearly has a system for eating lionish. Let's hope other groupers watch and learn and the technique spreads.