MOVEMENT IN FISH
• Fishes are vertebrates which live in water.
• All vertebrates have an internal skeleton made up of bones; a tough, elastic substance called cartilage; or both.
• Most fish have a streamlined shape - the head and the tail is narrow; the middle portion of the body is broader.
• This kind of shape offers least resistance to the flow of water and makes it easier for them to swim through water.
Fish have streamlined shape
• Fishes have fins and a flexible backbone that help them in swimming.
Fins and tail help in swimming
• Most fish have a special structure called swim bladder that can be filled with air or emptied to help them to move up and down in water.