Starfish Facts for Kids - What is a Starfish?

Starfish belong to the same group of invertebrates that live in the sea. 
These animals are echinoderms, which means "spiny skinned".
Starfish are flatter and have disk-shaped bodies, with a number of arms around the outside of the central body.

Most starfish have five arms, but some species have as many as fifty! 

If we turn a starfish, we'll see hundreds of tiny, sucker-like tubes waving about on the undersides of its arms. These are tube feet, and they are very useful to the starfish.
The suckers on the tube feet can stick to rocks or shells. The starfish moves along by pushing out, or extending, the tube feet on one of its arms so that they will stick to a nearby rock or to the seabed.
When the tube feet shrink, or contract, the starfish is pulled forwards.
Each tube foot has little strength, but hundreds of tube feet together are much stronger.
Starfish use their tube feet to pull apart the shells of clams and oysters so that they can eat the soft flesh inside.
To eat, the starfish pushes its stomach out of its mouth and folds it around the food!
Starfish are not fish and do not have gills to take in oxygen from the seawater.
Instead, they use their tube feet to absorb oxygen from the water.