Curr. Biol. 28, 2445–2451.e3 (2018)

Zebrafish are social animals—that makes them useful for studying the mechanisms that underlie social behavior. To better understand how zebrafish socialize, researchers at the University of Oregon have developed a new visual assay. They devised two tanks separated by an electrochromic film that can either be transparent or opaque. When fish in the tanks were allowed to see each other, they noticeably changed their swimming orientation towards one another. Dosing the tanks with a dopamine receptor agonist, which disrupts social interactions in mice, impaired the behavior in the zebrafish too. Physically and genetically altering the telencephalon, a region of the fish brain involved with social behavior that is homologous to structures in mammals, yielded similar results.