Clown anemonefish have territorial tendencies. Unlike the freewheeling, fun-loving protagonist of Finding Nemo, real life clown anemonefish are extremely hostile – even toward human divers. "I have ...

New research suggests that the fish may be counting vertical bars on intruders to determine their threat level, and to inform the social hierarchy governing their sea anemone colonies. Figure showing ...

Several anemonefish or clownfish share one anemone, with the largest fish being a female. This is a trio of common clownfish (Amphiprion ocellaris). Dauin, Philippines. (Credit: Klaus Stiefel / CC ...

We often think of fish as carefree swimmers in the ocean, reacting to the world around them without much forethought. However, new research suggests that our marine cousins may be more cognizant than ...