I love to eat fish.

Fish is by-and-large my favorite dietary source of protein, and living in Hawai`i means that I get to indulge in this adoration for finned flesh perhaps more often than I should. In the islands, there are plentiful, fresh fish of a staggering diversity sold and consumed everywhere you turn; firm and buttery a`u (Pacific blue marlin, Makaira nigricans), rich opah (Lampris regius), ubiquitous mahimahi (Coryphaena hippurus) and `ahi (Thunnus), lean and flaky ono (Acanthocybium solandri), and delicate `opakapaka (Pristipomoides filamentosus) are just a few. There’s also uhu, ulua, aku, uku, mamo, manini, akule, palani, awa, ama`ama, u`u, opelu, nenue, kamanu, omaka, hapu`u, `ula`ula koa`e, moi, ukikiki, kahala, kala, umaumalei, wahanui, and moano too. Introduced species? Hawai`i has roi, ta`ape, and to`au. Great, glistening troughs of poke line the deli section of just about every grocery outlet on my island (Safeway, local chains….liquor stores), and upon seeing them, I inevitably have to command my legs to carry me away from a fate involving a plastic container of heaven, chopsticks, and a wallet seven dollars lighter.

There are a number of reasons why avoiding the reduced price special on the limu `ahi at the Liliha Foodland may be a wise decision for just about anyone (temporarily salvaged funds unconsidered). As with any food, there are inherent risks, and fish have a unique repertoire of ways they can make a regretful meal. Perhaps the most readily publicized is the health risk posed by the bioaccumulation of methylmercury in the tissues of a number of fish species typically taken as food by humans. One bite of a particularly metal-saturated swordfish steak isn’t going to promptly send you to tea with Alice and a rabbit, and the accumulation of the poison in humans takes time (and LOTS of contaminated fish consumption). But, there are more acute ways a fish filet can bite back. For one, the fish may be highly endogenously toxic, meaning that the fish embeds poisonous compounds into its own essence, it’s own bodily tissues. Pufferfish are well-known for this approach, and many species have organs loaded with tetrodotoxin (TTX), a naturally-occurring, chemical Angel of Death so potent that it makes cyanide look like fucking ibuprofen. Preparing pufferfish for the passage between human lips takes all the insane, brow-beading, calculated finesse of disarming a bomb, but despite the supreme level of care of highly-trained culinary experts, every so often, people drop dead after ingesting the fish. Really damn dead. There are also the ever-present risks of conventional, bacterial food poisoning and infection with parasites like tapeworms and roundworms, both of which are more likely to occur in the less-than-cooked form of fish (my personal favorite state of fish).

Yes, you potentially need to watch what you eat when it comes to fish, whether you risk the slow march of mercury toxicity or a weekend hovering over the world’s unhappiest toilet. These risks are generally understood and expected.

What isn’t expected from your seafood? That you might get high off of it.

The phenomenon is called “ichthyoallyeinotoxism” or “hallucinogenic fish inebriation”; both are just jargony ways of saying that, somehow, the catch of the day has you hearing colors. Occurrences are uncommon, but there are plenty of baffling records, ancient and modern, of humans coming away from their sea-borne suppers with more to worry about than a bit of lemon wedge-fueled acid reflux. Like how to convince the grumpy, five-headed emu in the corner of the room that you don’t have any millipedes hiding under your fingernails.

The actual inebriation scenarios vary greatly, between species of fish, and between intoxication events. Onset of symptoms can occur within minutes, or hours, and can last from a couple hours to more than a day. Sometimes there is gastrointestinal upset. Sometimes not. Often times, the sufferer endures a loss of coordination and balance, along with muscle weakness and a burning of the throat, but none of this is guaranteed either. Ichthyoallyeinotoxism, as a peculiar clinical feature, is more or less defined by the presence of vivid hallucinations and/or nightmares, and a capacity for intoxication in even cooked fish (suggesting that whatever compounds are responsible are also very heat stable). Typically, symptoms outside of the psychoactive effects tend to be pretty mild, and temporary, contrasting with the peripheral nervous system assault characterized by other forms of fish flesh poisoning (“ichthyosarcotoxism”).

Ichthyoallyeinotoxism has been reported in a diverse array of marine fish, but it has most regularly been associated with one species in particular; the Salema porgy (Sarpa salpa). This species of sea bream is common along the West and South coasts of Africa, as well as throughout the Mediterranean Sea. The Salema porgy is a rather conventionally-molded, petal-shaped fish that grows to about the size of a football, identifiable by glittery golden stripes that run the length of its body. The fish’s occasional ability to get humans hippy flipped has been recognized for ages, and Salema porgy (also referred to as “saupe”) was routinely eaten for recreational purposes across the Roman Empire. If these long-gone citizens were around today, they would likely regard Long John Silver’s as a glorious drug den franchise.

For centuries, the fish (like many other species of ichthyoallyeinotoxic, or “hallucinogenic”, fish) has been called “dream fish” or “dream bream” for its psychedelic effects. The reputation continues until this day, however, since poisoning happens only on occasion, the Salema porgy is far more commonly consumed in the typical way fish are: as a food, not as a drug.

But, every so often, this backfires in spectacular fashion. In 2006, two case reports were published concerning recent ichthyoallyeinotoxism events caused by Sarpa salpa ingestion, both occurring along the French Riviera. In 1994, one of the unfortunate diners (a 40-year old executive) made the poor decision to partake in some baked Salema porgy while on vacation. Within hours, he was feeling shitty, and during the night, became a veritable puke fountain. Weakness overtook him, and in his ill state, decided to call an end to his vacation and drive home. This effort was brought to an abrupt end due to the onset of hallucinations. These weren’t the oft-depicted whimsical, psilocybin mushroom-driven phantasms full of fairies, talking trees, and a feeling of oneness with the universe. No, this poor son of a bitch was sidelined by a waking nightmare full of visions of “aggressive and screaming animals.” His mellow thoroughly harshed, and now unable to drive on account of seeing giant fucking bugs outside of his car, the man thought it might be a good time to get some medical attention. All his vitals at the hospital seemed kosher, except for the part where he was losing his shit because he was having the worst trip of his life, and after a short stay, he came back to reality…apparently, and thankfully, completely unable to remember the psychological hell his maritime meal had put him through.

The second individual outlined in the publication was a 90-year old man who purchased the Salema porgy from a local fisherman in 2002. Little did he know that his sweet, elderly soul was about to be catapulted through the stratosphere and straight into Never Never-do-I-ever-want-to-be-this-high-again Land.

Within hours, he was bulldozed by auditory hallucinations consisting of human screaming and “bird squeals.” The retiree was apparently too terrified that the hallucinations were part of the sudden onset of a psychotic episode or mental illness that he told no one for the remaining three days of symptoms, which included frequent nightmares in addition to the general feeling of going bugfuck insane during waking life. It was only afterward that he recalled someone at the fish market saying something along the lines of “oh, just so you know…these fish are tasty but they can sometimes cage you in loop of mirrored realms full of hatred and the shrieking of dying universes” and decided to contact someone at the local poison control center.

Of course, the Salema porgy isn’t the only hallucinogenic fish out there. Sporadic records come from numerous other groups of fish, and one of these are the rabbitfishes. Rabbitfish, or “spinefoots”, are a group of fish native to the warm waters of the Indo-Pacific, and belong to the genus Siganus. The fish have a unique modification of the rear-facing fins; well-developed venom glands attached to spines making up the framework of the fin. These venomous barbs can be used defensively (and if the venom is used against humans, is not deadly, but can inflict excruciating pain), and are the origin of the decidedly more intimidating “spinefoot” common name.

Despite their rather nasty pokey bits, rabbitfish are commonly fished for food by humans who live along the coral-lined shores of tropical coasts and islands. With consumption of these little, herbivorous reef fish comes the risk of hallucinatory poisoning. Residents of the Mascarane Islands (particularly Mauritius and Réunion) in the Indian Ocean, east of Madagascar, have reported regular, occasional instances of fish poisonings with symptoms consistent with the ichthyoallyeinotoxism seen with Salema porgy in the Mediterranean; loss of balance and equilibrium, nightmares, hallucinations, and mental depression, all in an absence of major peripheral neurological distress (usually associated with more typical (and serious) exposures to neurotoxins from food; trouble breathing, sweating, blurred vision, etc.). Apparently, the people of Mauritius and Réunion have been aware of this unique property of Siganus fish for some time now (enough so so that one species, Siganus spinus, is consistently referred to as “the fish that inebriates”), and local fishermen have associated elevated risk with certain times of the year in their archipelago home, and can avoid inadvertently taking a surprise trip to see just how far down the rabbitfish hole goes…

There are also records of hallucinatory poisoning by rabbitfish in the Mediterranean; specifically by the dusky spinefoot (Siganus luridus). This fish is native to the Western Indian Ocean, Red Sea, and Persian Gulf, but has been introduced across the Suez Canal in recent decades, although the symptoms were also similar to more “conventional” poisoning by ciguatoxins and maitotoxins (which cause ciguatera; a seafood-borne intoxication derived from ciguatoxins from single-celled marine algae which become aggregated in the flesh of food fish…most commonly associated with big, tropical, carnivorous fish like grouper, barracuda, snapper, and amberjacks).

Over on the other side of the globe, out in the West and Central Pacific, ichthyoallyeinotoxism is also implicated in hallucinatory poisonings, but often with different groups of fish.

Mullets (Mugilidae), odd, flat-headed fish found in warm waters the world over, have been reported to be ichthyoallyeinotoxic here in Hawai`i, as well as in the Micronesian islands of Kiribati. The toxins appear to concentrated in the head of the fish, specifically. At least some residents of the Republic of Kiribati, in recent times, would consume mullet heads with the intention of getting really fucking high. The hope was that eating a nice, fishy meal, kicking back on a tropical beach, and, er, “chasing the saltwater dragon” would allow for pleasurable hallucinations and vivid, otherworldly dreams.

Also, particularly in Kiribati, coral groupers (Epinephelus corallicola) and the banded sergeant-major (Abudefduf septemfasciatus) have been reported to occasionally cause hallucinogenic episodes, specifically in older members of the local population (the only age group that eats these species customarily; kind of like butterscotch hard candy and prunes here in the U.S.). Although, since only senior citizens eat these fish, and the high was described as a kind of “forgetfulness”, it’s not clear whether or not the issue is inebriation or run-of-the-mill senility. Then again, if people were accusing my old ass of spending my Golden Years getting toasty off the silly sushi, I might get awfully “forgetful” myself.
“What?! No, grandson, of course I’m not a stoner! That’s just Alzheimer’s.”

Sea chubs of the genus Kyphosus (pictured below), commonly eaten in Hawai`i in historical times (less so recently), have also been reported to induce intense hallucinations in diners.

Similarly in Hawai`i, convict tang (Acanthurus triostegus), a species of surgeonfish found throughout the Indo-Pacific, has been associated with ichthyoallyeinotoxic poisonings. The species (known as “manini” here in the islands) is abundant in nearshore reef habitat, and is readily identifiable by its markings, which resemble the stereotypical stripes of an inmate’s jumpsuit uniform…a criminal sentence most likely endured due to the fish spreading the scourge of drugs across their ecosystem.

So what is behind these hallucinogenic compounds? Why are only a limited group of fish associated with ichthyoallyeinotoxism, and why does it seem to only effect people relatively rarely? Other sources of hallucinogens in nature are, by and large, far more predictable than this. There may be variances in dosage between individuals, but many times, particular, entire species are known to have hallucinogenic qualities. Examples of these abound. Psilocybin or “magic” mushrooms and ergot (from which ergotamine, and eventually LSD, were isolated) are the hallmark psychedelics of the Fungi kingdom. The number of psychedelic plant alkaloids and other compounds, many of which play spiritual and cultural roles in societies around the globe, is incredibly high: mescaline from cactus (including peyote), bizarre and terrifically potent terpenoids like salvinorin A from the famed diviner’s sage, and DMT from dozens of vines and shrubs, are just a few major examples. DMT variants found in the toxic secretions of toads like Bufo alvarius also have consistently extremely psychoactive, hallucinatory properties. If we can identify specific plants, fungi, and animals that produce hallucinogenic effects, then what’s the deal with the weird, wishy-washyness of these hallucinogenic fish?

Since ichthyoallyeinotoxism is not a very common variety of food fish poisoning, and it presents so variably, we don’t really know much about it, or what is actually causing it, specifically. But, given how the phenomenon appears to be temporal, tied to seasonality in some locations, and is so highly variable, it is thought that the source is dietary. The fish are getting the toxins from their food, and much like with the mercury so many of us are familiar with, accumulating the stuff in their tissues. Since so many species that are causing these effects are herbivorous, it is likely the original source is marine algae.

This is strikingly similar to the most common form of poisoning from food fish, ciguatera. Ciguatera is caused by the uptake of a specific group of microscopic algae; dinoflagellates (chiefly the species Gambierdiscus toxicus). It accumulates in the food chain, compunding as one ascends, so that reef predators have the highest concentration of the toxins in their flesh (and are therefore most commonly reported to cause severe poisonings when consumed). Ichthyoallyeinotoxism does have a quite a bit of suspicious overlap with ciguatera, and it’s often hard to tell the two ailments apart from one another. For one, the species of fish that cause hallucinogenic poisonings are also commonly associated with ciguatera records as well. Secondly, the symptoms are incredibly similar, and both impact the nervous system in a myriad of bizarre ways. These similarities, and the lack of a specific source of the much rarer ichthyoallyeinotoxism has led some to believe that ichthyoallyeinotoxism is just one manifestation of ciguatera (which is caused by several known algal toxins).

However, the two maladies have distinct differences as well. Ciguatera is typically accompanied by furious digestive problems, muscle pains, lots of weird disruption of the peripheral nervous system (reversal of hot and cold sensations, electric charge sensations, and numbness) and only mild to occasional instances of hallucinations, whereas ichthyoallyeinotoxism has benign bodily impacts, with most effects on the central nervous system (the brain itself, leading to the hallucinations and nightmares). Also, ciguatera is notorious for long-term, pernicious effects, which can be severe enough to cause disability a decade or more out from the initial poisoning. Ichthyoallyeinotoxism, in contrast, abates completely within a few days with no reported latent effects in weeks, months, or years down the line. Hallucinogenic poisoning also turns up in places not typically associated with the normal range of the algae associated with ciguatera, like the Mediterranean (ciguatera tends to crop up most typically in the Caribbean and Pacific regions).

Others have postulated that the toxins might have their own, separate origins in algae like Caulerpa, which are habitually consumed by many of the more commonly hallucinogenic fish species.

Whatever is causing the occasional flaky, delicious acid trip in tepid seas, it shouldn’t be of huge concern to anyone reading this (or object of recreational interest; good luck successfully being lucky enough to be in the right place at the right time). Ichthyoallyeinotoxism remains an uncommon and enigmatic phenomenon, far less so than ciguatera or red tide shellfish poisoning (which are still not all that common, thanks partially to awareness campaigns and harvesting advisories during algal blooms). Mercury toxicity shouldn’t really be high on your list….that is, unless you are pregnant, or insist on eating canned tuna by the flat.

Honestly, the real source of caution seafood lovers such as myself should take is towards regulation of consumption. Many fisheries of popular food fish (Pacific bluefin tuna comes to mind) have been subject to extreme population reductions and are threatened with collapse. The effects not only impact human culinary lives and employment, but inevitably reverberate through entire marine ecosystems. Some stocks are in better shape than others, and are harvested in more sustainable ways than others. If you want to be selective with your seafood choices, your time and effort might be better spent keeping conservation in mind, not the risk of turning your mundane Thursday night into a disorienting, hallucinatory hellscape.

Image credits: Phish concert image, rabbitfish, sea chub (John Turnbull), convict tang

Intro image composite, modified from the following: Lionfish (Michael Aston), pufferfish, mandarin fish (Klaus Stiefel), lagoon triggerfish (Michelle Bender)

© Jacob Buehler and “Shit You Didn’t Know About Biology”, 2012-2014. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Jacob Buehler and “Shit You Didn’t Know About Biology” with appropriate and specific direction to the original content.