March 9, 2026 — Nanoplastics are disrupting fish’s ability to think and make decisions, with troubling implications for ocean food webs.

What’s happening?

Scientists from Shantou University, the Chinese Academy of Fisheries Sciences, and Charles Darwin University wanted to find out how tiny plastic particles affect brain function in marine fish.

According to the study, published in the journal Marine Pollution Bulletin, they introduced polystyrene nanoplastics into the tanks of marine medaka, a small fish species, then ran the animals through a maze.

Fish that had been in contact with nanoplastics rushed through choices and stumbled at higher rates than their unexposed counterparts. That kind of impulsive behavior could spell disaster in open water.