Fish have a brain microbiome.

“Recently, a study published in Science Advances provided the strongest evidence yet that a brain microbiome can and does exist in healthy vertebrates — fish, specifically. Researchers at the University of New Mexico discovered communities of bacteria thriving in salmon and trout brains. Many of the microbial species have special adaptations that allow them to survive in brain tissue, as well as techniques to cross the protective blood-brain barrier.” Two implications: 1) we may have one too; 2) those microbes may be influencing our actions (like our gut microbes already do). ~ learn more