The fang blenny fish’s two-inch body is not very intimidating to predators, and its pair of teeth give it the look of a braces-wearing teenager. But those canines pack a chemical punch, helping the fang blenny escape the maw of would-be bullies.
In a report published in Currently Biology, researchers found that fang blennies’ venom includes three components. The first is a neuropeptide — little protein-like molecules that help neurons pass information — that occurs in venom from predatory cone snails. Also present was a lipase, a digestive enzyme, “similar” to those found in scorpions, and an opioid peptide. Opioid peptides in the brain, among other things, are important to pain and stress response. When a fang blenny bites a would-be attacker, the chomp is likely to cause a drop in the blood pressure of its target. Study co-author Bryan Fry surmises that this combination “can produce sensations of extremely unpleasant nausea and dizziness.” While the predator is reeling, the fang blenny flees.
Fry compares this to fish with venomous dorsal spines, which he says “produce immediate and blinding pain” when they inject their venom, also known as envenomation. When someone falls victim to a stingray, for example, it’s hard not to notice you’ve been barbed. “The most pain I've ever been in other than the time I broke my back was from a stingray envenomation,” Fry says. “'Sting' ray sounds so benign. They don't sting. They are pure hell."
Whether or not there’s pain involved a fang blenny bite — aside from, you know, getting bitten — is hard for researchers to say. These little fang blennies only inject a little amount of venom into their attackers. At the very least, the rodents on which Fry tested the venom did not experience pain. "For the fang blenny venom to be painless in mice was quite a surprise," says Fry, known stingray survivor.