Move over, coked-up salmon. Fish dosed with psilocybin, the psychoactive component found in magic mushrooms, showed less aggression toward peers compared to their normal behavior in laboratory experiments, according to a study published on Thursday in Frontiers in Behavioral Neuroscience.

Scientists have studied the effects of psilocybin on humans and a variety of other mammals, but fish offer unique insights into the effects of this compound due to their wide varieties of social structures and activity levels. The research is the first to “demonstrate that psilocybin reduces aggression in any animal model,” according to the study, and opens the door to future studies that might pin down the neural mechanisms that underlie these behavioral changes.

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404 MediaBecky Ferreira

The mangrove rivulus fish (Kryptolebias marmoratus) is particularly intriguing as a highly aggressive fish with incredible adaptations, including the ability to survive out of water for months at a time. It is also a rare hermaphroditic species that reproduces mainly through self-fertilization, producing clones that remove genetic variation as a factor in experiments. 

“Each lineage that we have is essentially genetically identical, and between lineages, they are genetically distinct,” said Dayna Forsyth, a research associate at Acadia University in Nova Scotia who led the study, in a call with 404 Media. “So, we eliminate the genetic factor, and just focus on the behavioral effect.”

To determine how psilocybin influences behavior in these fish, Forsyth and her colleagues placed two undosed fish on opposite sides of a tank with a fiberglass mesh barrier that allowed the fish to see and smell each other, but prevented physical interactions. Then, the “focal fish” was removed and exposed to a low psilocybin dose in a separate tank for 20 minutes, and was later transferred back to the partitioned tank where its responses to the undosed “stimulus fish” were observed.

“We really had no idea what we were getting ourselves into,” Forsyth said. “We didn't have much to go off of before. My research question throughout was just: ‘does psilocybin affect fish behavior?’ We had no idea when we first started this, because there weren't too many papers out there on fish.”

As it turned out, psilocybin had a noticeable impact on the behavior of these fish. Mangrove rivulus fish express aggression by suddenly darting at peers in swimming bursts, but these charges were noticeably reduced in the psilocybin-treated fish. However, the fish still interacted in less overtly hostile ways—such as performing lateral and head-on displays meant to size up  peers—regardless of whether they had been dosed.  

“We definitely predicted that all aggressive behaviors, including those lateral and head-on displays, would be decreased,” Forsyth said. “We really did not expect it to just target that highly aggressive and more energetically costly behavior, rather than the low-energy behaviors. That was definitely a surprise.” 

The study adds to a growing body of research about the impacts of psychoactive compounds on fish, including a recent study in Current Biology about salmon that were exposed to cocaine.

Similar experiments could eventually yield insights about the effects of psilocybin, and other substances, on humans, given that we share some neural anatomy with fish. Forsyth is also interested in how an increased dose might affect fish, or whether they might develop a long-term tolerance to the compound that might shift their behavior back to a normal aggressive state.

“In terms of toxicology studies and exposing fish to a compound for a medicinal aspect, you always want the lowest dose that creates the outcome,” she said. “But it would be interesting to increase that dose and see if it almost reverses the effects. We don't know, but it would be interesting to see what that tolerance is for the dose, maybe even with repeated exposures over time.”

Cap of 20mph in towns and cities and 60mph on motorways would cut fuel demand and combat rising prices, IPPR says

Britain should lower speed limits for drivers as part of a package of measures to reduce the impact of the Iran war on consumers, a thinktank has said.

Capping legal speeds at 20mph in towns and cities and 60mph on motorways would help reduce fuel demand and combat soaring oil prices triggered by conflict, according to the Institute for Public Policy Research (IPPR).

Parents say the insistence on Mandarin in schools is eroding the country’s language and culture right from early childhood

Weeks after a Tibetan-speaking five-year-old started preschool, she had “completely stopped speaking Tibetan”, according to her mother. Nine months later, although the child could still understand Tibetan, she only answered in Mandarin, and at best a few single-word answers in Tibetan after some time.

Instead the girl “keeps saying that she can only speak Chinese … that she is Chinese and not Tibetan”, according to a researcher who met the family. “The mother thinks that the daughter is just repeating what she is constantly told at school and that the government aims to eradicate Tibetan.”

Al Nahyans’ control over farmland in Europe has meant they receive proportion of payments to farms

The United Arab Emirates’ ruling royal family is benefiting from tens of millions in EU subsidies to grow crops destined for the Gulf, it can be revealed.

A cross-border investigation by DeSmog and shared with the Guardian found subsidiaries controlled by the Al Nahyans collected more than €71m (£61m) in six years for farmland it controls in Romania, Italy and Spain.

To celebrate Sir David Attenborough’s centenary, Madeleine Finlay catches up with natural history writer Patrick Barkham, who has met the celebrated presenter. They explore how the natural world has changed in the century that Attenborough has been on Earth, and how his programming has reflected his growing commitment to highlighting the devastating impacts of the climate crisis on nature and biodiversity

Clips: BBC, PBS

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Exclusive: Voters remain split on issues critical to EU, such as support for Ukraine and dependence on Russian energy

More than three-quarters of Hungarians who voted for Péter Magyar in last month’s election want his government to do more to address the climate crisis, and more than 70% want him to protect LGBTQ+ rights, a poll has found.

Magyar’s opposition Tisza party won a supermajority in the vote, bringing an end to Viktor Orbán’s 16 years in power. The new prime minister will be sworn in on Saturday, weeks after the results set off celebrations in Budapest and Brussels.

Exclusive: Documents obtained by consortium of journalists show role of Moscow university in training operatives in military intelligence

Last April, Vladimir Putin visited the campus of Bauman Moscow state technical university, set on the banks of the Yauza River in the east of the city and home to some of the country’s brightest scientific minds.

He toured the campus, met undergraduates and boasted about Moscow’s ambitious plans for space missions to the moon and Mars. “You have everything it takes to be competitive,” Putin told the students.

Let’s not draw the wrong conclusions from Hungary’s election or the US president’s troubles

Viktor Orbán’s crushing defeat in last month’s Hungarian election has led to an outbreak of democratic optimism. Across the globe, democrats are drawing lessons from the results and speculating about the decline of the far right. There is simultaneously a consensus that Donald Trump has gone from inspiration to “liability” for the global far right.

While the fall of Orbán has great symbolic significance and important consequences for EU politics (see the EU-Ukraine deal), we should be very careful not to read too much into it for three reasons.

Cas Mudde is the Stanley Wade Shelton UGAF professor of international affairs at the University of Georgia, and author of The Far Right Today

Eight birds play the lead in Hen – one for running scenes, one for pecking, one for staying still. And there’s even a cockerel love interest. Director György Pálfi explains why it’s his most normal movie yet

If oppressive regimes inadvertently give rise to striking artistic works of resistance, then Hen might just be a parting gift from Viktor Orbán’s far-right regime. This compelling, original film, told from the perspective of a hen, was only made because Hungarian film-maker György Pálfi could no longer create anything in his home country. Orbán’s 16 years of cronyism banished any chance of funding a film in Budapest, so Pálfi – who has directed eight wildly original films, from his near-wordless 2002 debut Hukkle to 2006’s visually striking and grotesque Taxidermia – was driven into exile. Searching for a universal story he could tell even when filming in a culture or country he didn’t fully understand, he and co-writer and partner Zsófia Ruttkay settled on a biopic of a factory-farmed chicken.

The hen escapes her gruesome, industrial birthplace in Greece and, through her naturally comic beady eyes, we witness the unfolding of a modern-day Greek tragedy, whereby a down-at-heel restaurateur is drawn into the brutal world of people-smuggling.