Starfish do not have a brain at all. Instead, they use a decentralized nervous system made of a nerve ring and nerves in each arm to sense their surroundings and coordinate movement.

Quick Scoop

  • Starfish have zero brains, not one and not five.
  • They have a nerve ring around the mouth plus radial nerves running down each arm that act like a simple control network.
  • Each arm can sense light, chemicals, and touch and can move quite independently, which is why a detached arm may keep moving for a while.

How They Work Without a Brain

  • Their decentralized nervous system lets them:
    • Detect food and danger.
    • Coordinate hundreds of tube feet to crawl along the seafloor.
    • Regenerate lost arms over time.
  • Because there is no single central brain, the “decision‑making” is spread out through the nerve ring and arms rather than happening in one organ.

TL;DR: If you are asking “how many brains does a starfish have,” the accurate answer is: none at all, just a clever, spread‑out nervous system.

Information gathered from public forums or data available on the internet and portrayed here.