As reported earlier today, a Sarpa salpa fish has been caught in British waters, the first one since 1983 and the fourth one ever reported from the United Kingdom. The fish received a lot of attention, not only for being so far out of its normal range but also for being, well – far out in general. Sarpa salpa sports golden stripes along its body and can cause hallucinations in humans when ingested; hallucinations that may last for several days.

For anyone interested in knowing more about this remarkable little fish, researchers Pommier and de Haro of the Toxicovigilance Centre Antipoison at Marseille’s Hospital Salvator have conducted a clinical study on two patients who started seeing and hearing strange and frightening things after dining on Sarpa salpa in southern France.

According to the study, which was published in the journal Clinical Toxicology in 2006, ichthyoallyeinotoxism –i.e. hallucinogenic fish poisoning – can occur when you eat the head or body parts of certain species of herbivorous fish which in turn have been devouring large amounts of certain algae or phytoplankton. The substances believed to be responsible for the long-lasting trips are known as indoles and their effect on the human brain is similar to that of lysergic acid diethylamide (LSD).

Sarpa salpa is not the only fish capable of causing vivid hallucinations and nightmares in unsuspecting dinner guests; several species of tangs, damsels, mullet, goatfish and

rabbitfish can give you a similar experience if they have been eating large amounts of algae or phytoplankton filled with indoles. Ichthyoallyeinotoxic fishes are colloquially referred to as ”dream fishes” and until 2006 ichthyoallyeinotoxism had only been reported from the Indo-Pacific.

The two men studied by Pommier and de Haro suffered from CNS disturbances including terrifying hallucinations and nightmares after being served Sarpa salpa in a Mediterranean restaurant. One of them, a 90-year old man, suffered from auditory hallucinations a couple of hours after eating Sarpa salpa, followed by two nights of vivid nightmares. The second man, a 40-year-old, was admitted to hospital after developing not only terrifying visual and auditory hallucinations but digestive problems as well. For him, the psychedelic experiences didn’t trickle away until 36 hours later.

The popular food fish Sarpa salpa is normally not hallucinogenic but if you do get poisoned your mind might start playing tricks on you within minutes and the effects may last for several days; usually without causing any other health problems. There is no antidote. According to the paper, ancient Mediterranean’s used Sarpa salpa as a recreational drug during the reign of the Roman Empire.

We still know very little about the possibly mind-altering effects of algae-eating fish and there are reports of certain fish species, e.g. Kyphosus fuscus, containing even more potent hallucinogens than indoles, such as dimethyltryptamine (DMT).

For more details see the paper: de Haro L, Pommier P (2006) -

Hallucinatory fish poisoning (ichthyoallyeinotoxism): two case reports from the Western Mediterranean and literature review. Clin Toxicol (Phila). 2006;44(2):185-8.