In one lab study, yes. Researchers at Acadia University and the University of British Columbia gave adult mangrove rivulus fish (Kryptolebias marmoratus), a naturally aggressive species, a single low dose of psilocybin, the psychedelic compound in “magic” mushrooms, by placing them in treated water for 20 minutes. When the fish then faced the same rival through a mesh barrier, they moved around less and made fewer high-energy swimming bursts, the behavior that signals an escalating attack.
Lower-energy social displays, such as head-on displays, stayed largely unchanged, so the compound dampened escalated conflict without shutting down social behavior. The team only tested single short exposures and cautions that the results are not evidence of a treatment for aggression in people. The study was published in Frontiers in Behavioral Neuroscience (DOI 10.3389/fnbeh.2026.1767175).
Image: mangrove rivulus (Kryptolebias marmoratus) at the Aquarium tropical du Palais de la Porte Dorée, Vassil, CC0, via Wikimedia Commons.
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