‘Not unlike the ant-decapitating fly and the satanic leaf-tailed gecko, the fang blenny’s name does not disappoint. This tiny fish wields two massive teeth that it uses to gouge chunks out of much larger fish and, in a bind, scrap its way out of the grasp of a predator. And one particular group of fang blenny even injects venom, just like a snake, to give its attackers that extra what-for.
That’s all very, very bizarre behavior for a fish—behavior that today gets even more bizarre. In the journal Current Biology, researchers have revealed what makes the fang blenny’s venom so unique: It’s packed with opioid peptides, which target opioid receptors, much like heroin and morphine do in the human brain. Unlike with snakes or stingrays or the infamous lionfish, the venom doesn’t incapacitate the victim with pain. Instead, it sends the fish’s blood pressure plummeting, messing with its coordination and giving the blenny a chance to escape…’