Sea stars (we don’t call them starfish anymore, because they’re not really fish!) have five arms, each with its own set of respiratory, digestive and reproductive organs!
Each arm also has hundreds of tiny tubefeet that enable the starfish to creep slowly over the reef.
Don’t worry if you see a starfish with only four or even three arms. Starfish can regrow their arms – in fact a single arm can regenerate a whole body!
Feeding inside out
The mouth is on the underside and the anus on the topside.
Starfish feed by turning their stomachs inside out and releasing enzymes to digest the food externally. It can take a starfish several hours to pull a mussel apart and slowly digest it.