Fish are vertebrate animals that live in the water. Vertebrate means they have a spinal cord surrounded by bone or cartilage.

Fish have an organ called gills that take in oxygen from the water around them.

There are over 30,000 known species of fish.

A tuna is the fastest fish in the ocean.  Tuna can swim 43 mph.

Fish are covered in scales which are often covered in a layer of slime to help their movement through water.

Cleaner fish help out other fish by removing parasites and dead skin from their scales.

Over 1000 fish species are threatened by extinction.