Fang blennies (Meiacanthus grammistes) may look like just another species of small and colourful Pacific fish but they pack a very serious bite.

Sporting large canine fangs on their lower jaws which slot neatly into holes inside the upper part of their mouths, the little fish are also appropriately known as saber-toothed blennies and can deliver a powerful dose of venom to any predators that are unwise enough to mess with them.

But while venomous fish are common in the oceans, the great majority deliver their toxins through spines on their backs. Fish with venom-injecting fangs are much rarer and the fang-blenny’s venom itself is something quite special. In a new study, researchers analyzed venom samples from the fishes' tiny fangs and found that it produced a very different effect from venom delivered through spines, which usually triggers excruciating pain.

They found a chemical cocktail that performed like morphine or heroin, making the blenny’s attackers dizzy and sluggish when bitten. This in turn dulls the predator's coordination and affects its ability to swim, enabling the blenny to escape. Scientists even reported observing blennies being swallowed by larger fish, which then jerked and shook their heads, then spat the blenny out unharmed.

Further study of the venomous cocktail revealed that it’s completely unique to the fang blenny and that the compounds within it have pain-inhibiting properties that could be used to develop a whole new range of powerful pain-killing drugs.

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