June 18, 2025, 1:48 pm | Read time: 5 minutes

In the Caribbean, there is a specific pufferfish that sea turtles love to eat. However, the fish’s toxin gets them so high that they risk drowning. PETBOOK author and biologist Saskia Schneider explains the curious phenomenon behind this.

Why Pufferfish Are So Toxic

The Caribbean sharpnose puffer contains–like all pufferfish–the toxin tetrodotoxin. This is a potent neurotoxin, primarily known from the cosmetic field, where it is used under the name Botox to combat wrinkles. In fact, it is one of the strongest poisons in the world. As a sodium channel blocker, it inhibits communication between nerve cells–and thus muscle contraction. This leads to paralysis and even death. ¹

And as if that weren’t enough, the Caribbean sharpnose puffer has a second toxin, saxitoxin, which has been detected in only a few pufferfish species. The mechanism of action is the same as tetrodotoxin. Together, they cause severe poisoning and paralysis–even in very low concentrations.

Do Sea Turtles Really Get High?

Surprisingly, sea turtles do not die immediately when they eat the fish. Many animals initially lose the ability to move and sink to the bottom. This gives observers the impression of relaxation–similar to when humans consume cannabis. Perhaps this is why popular media occasionally use the phrase that sea turtles get high from the fish. Whether the animals actually have “stimulating thoughts” like on a trip remains the secret of the reptiles.

However, the behavior of another marine animal suggests that pufferfish toxins can indeed induce a state of intoxication. Dolphins have been observed deliberately nudging pufferfish. Researchers suspect that this is not just play behavior, but that the animals actively get high, as they touch the pufferfish very cautiously. ²

In human medicine, tetrodotoxin is rarely used. Therefore, there are few descriptions of possible states of intoxication. Studies show, however, that it can potentially be a very effective painkiller and even a good alternative to opiates. In Chinese medicine, it is described that pufferfish toxin can have a strengthening effect when properly dosed. Its main use was in the “suppression of seizures.” ³

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Why Do Turtles Eat the Fish at All?

But why do sea turtles repeatedly eat Caribbean sharpnose puffers if they are so highly toxic? Perhaps they really do have a good trip and actively seek the thrill? Much more likely, however, is that the fish seem to be an attractive prey for the turtles. Although the toxin is supposed to give a terrible taste, the amount of toxin in a pufferfish can vary greatly–even within the same species in the same ecosystem.

However, the question remains why the pufferfish’s second defense mechanism does not prevent them from being eaten. The small fish are not only toxic, but they also inflate–as their name suggests–into a ball. The Caribbean sharpnose puffer’s ball is only the size of a softball–about four inches in diameter–but the skin is studded with spines. Who would want to take a bite of that? Studies show that many turtles eat not live but dead specimens. This becomes a problem, especially when there are suddenly many dead pufferfish.

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Can Even Trigger Mass Deaths

In the years 2013, 2014, and 2017, there were mass deaths of sea turtles on the coast of Costa Rica. The green sea turtle (Chelonia mydas) was particularly affected. Investigations by a U.S. research team concluded that the many dead animals were linked to a mass die-off of Caribbean sharpnose puffers. Although green sea turtles primarily feed on plants, they do not disdain dead fish when the opportunity arises, the scientists write.

They found numerous pufferfish in the stomachs of the turtles. Most animals died from poisoning and the resulting paralysis, according to analyses. However, two animals were rescued alive and fully recovered after 24 to 48 hours. The toxin does not always seem to kill the turtles immediately, as numerous eyewitness reports confirm, in which divers and animal rights activists report rescuing sea turtles that were upside down or motionless on the seabed.

Why mass deaths of sharpnose puffers and consequently sea turtles occur repeatedly could not be clarified. However, researchers suspect it may be related to the mass immigration of juveniles into feeding areas. Similar occurrences have been observed in other pufferfish species.

Conclusion:

The Caribbean sharpnose puffer (Canthigaster rostrata) poses a dangerous yet apparently enticing food source for sea turtles. This can lead to severe poisoning and paralysis, which in some cases results in death or–if things go better–rescue by divers. Although some observations suggest a state similar to intoxication in the animals, it remains unclear whether the sea turtles actually get high or consciously seek a state of intoxication. What is clear, however, is that the combination of natural toxicity and animal behavior poses a serious risk to endangered sea turtles.