Okinawa, Japan

Meet the Stonefish

The most venomous fish in the world

We don’t often think of venom in fishes. Instead we commonly focus on animals such as snakes, spiders, and scorpions when listing the world’s deadliest creatures. We should reconsider.

It is estimated that there are more venomous fish than snakes. Venomous fishes can be found in fresh and saltwater, in habitats ranging from alpine streams to coral reefs. This spring I had the opportunity to meet one of the most venomous fish of them all: The stonefish.

Dan Warren , Teresa Iglesias and I were working in a tide pool area during a late night low tide outside of the Okinawa Institude of Science and Technology . About an hour into our work Dan called out and we went to see what he was excited about. In a few inches of water was a massive stonefish.

Stonefish Encounters

We all knew this fish was venomous, but it wasn’t until we did a little reading that we discovered how venomous. Stonefish are potentially lethal. Unlike other icons of the venom world like snakes or spiders, stonefish venom isn’t injected through a bite. Instead venom is injected through their fin ray spines on top of the fish. Basically, you step on them and it activates the venom injection mechanism. Luckily these fish are not at all aggressive and do not seek out trouble with people. Think of them more as a really dangerous rock that likes to eat fish once in a while.

That said, people often do wind up stepping on stonefish. It is easy to see why. If you are looking for a stonefish, the ideal search image really is a rock with some algae on it. Here is an image of the one we found out of water.

Now here is an image of where we were walking.

Finding a specific rock in a tide pool is not exactly easy. But stonefish don’t restrict themselves to tidepools. It turns out that stonefish can live out of the water for up to 24 hours. This now means you have to be looking for your specific rock anywhere on the beach.

How often people actually step on stonefish?

We can look to Australia for some insights on this. First of all, thanks to antivenom, no one down under has been documented as dying from a stonefish since 1915. That said, envenomations are not rare. In Australia alone there are between 700-1000 uses of stonefish antivenom annually. Now remember that these animals range from the Red Sea through most of the tropical Indo-Pacific. Dan discovered this video by Smarter Every Day that goes behind the scenes to document the lab that helps meet the demand of stonefish antivenom. Check it out and if you ever find yourself in the tropical pacific, watch your step!

Dialogue & Discussion