1. The class of fishes is called Pisces. They are aquatic vertebrates.
2. According to their size and shape, the fishes are of many kinds.
3. They have a head, a trunk and a tail.
4. The head and trunk are directly jointed together and neck absent.
5. Body of fish is flexible tapering at both ends and streamlined. This type of body helps in swimming.
6. They can swim with fins, which are attached to the trunk.
7. They body is covered with scales which remain moist by special type of secretion of body.
8. Breathing organs are gills which are present in the hollow spaces found on both sides of the head for exchange of gases i.e. oxygen and carbon dioxide.
9. Mouth has teeth, which is used for grasping instead of grinding of food.
10. In some fishes air pouch is present, which is called air bladder. The air bladder is used for buoyancy.