The Sarpa salpa fish, a species of sea bream known as the dreamfish or salema porgy, is widely distributed across the Eastern Atlantic and Mediterranean Sea. This fish possesses unusual characteristics, including a unique diet among its family and, under certain conditions, a startling effect on human consumers. This dual identity, shifting from a common coastal fish to a source of vivid, frightening hallucinations, makes the Sarpa salpa a subject of fascination.
Distinctive Appearance and Range
The Sarpa salpa is the sole species in its genus, Sarpa, within the Sparidae family. This fish has an oval, moderately slender body, typically reaching 30 centimeters, though specimens up to 51 centimeters have been recorded. Its coloration is highly recognizable, characterized by a silvery-gold body crossed by eight to twelve conspicuous golden stripes running the length of its sides.
The species is found throughout the Mediterranean Sea and the Eastern Atlantic Ocean, ranging from the Bay of Biscay down to South Africa. It is also present around the Azores and Canary Islands. The Sarpa salpa is a strictly coastal fish, preferring shallow waters down to about 70 meters. It schools gregariously over rocky bottoms and in meadows of seagrass, such as Posidonia oceanica.
An Herbivore of the Sea
The diet of the Sarpa salpa is a biological distinction, as most of its sea bream relatives are carnivorous. This fish is a primary herbivore, consuming marine plant matter, a characteristic that develops as the fish matures. While juveniles consume plankton, adults graze heavily on seaweeds, marine algae, and especially on seagrasses like Posidonia oceanica.
To process this tough, fibrous material, the Sarpa salpa possesses specific anatomical adaptations. Its small mouth and dentition are highly adapted for an herbivorous lifestyle. It has a single row of sharp, incisor-like teeth on both jaws, which scrape and cut plant matter from the substrate. Furthermore, its gut length is notably longer—about 3.3 times longer—than that of its carnivorous relatives.
The Psychedelic Fish
The Sarpa salpa has the potential to induce vivid hallucinations when consumed, a rare form of food poisoning called ichthyoallyeinotoxism. Historical accounts suggest the psychoactive effects of the “dreamfish” were known to the ancient Romans. The effects involve disturbing visual and auditory hallucinations that can last for more than 36 hours.
The neurotoxic effect is acquired through the fish’s diet via bioaccumulation. When the fish grazes on seagrass, it ingests epiphytes—small organisms and algae growing on the leaves. These ingested materials can include toxic dinoflagellates, which produce potent neurotoxins related to ciguatoxins. These toxins are then stored in the fish’s organs, particularly the liver and viscera.
The toxicity is highly variable, depending on geographical and seasonal factors. Reports of poisoning often peak in late spring, summer, and autumn, correlating with the seasonal proliferation of the toxic algae the fish consumes. Symptoms, which include dizziness, loss of coordination, and frightening hallucinations, are a direct result of these accumulated neurotoxins.