How do fish move?

Answers:
Basic swimming is done by using the tail for forward motion. The brain sends impulses to the muscles via the nervous system. As previously mentioned, this is done because the muscles and spine are connected, so as a fish contracts and relaxes its muscles, the tail bends. How much of the tail is used for swimming depends on the fish: http://www.advancedaquarist.com/issues/m... Some only use the fin and a very short part of the body while other fish get more of their body involved.

Long, thin fish like eels have to rely more on body movement and create a series of curves, much like the motion of some snakes to push against the resistance of the water.

To change directions, the fish uses its other fins (the paired ones) either together or opposing one another.

The swim bladder provides buoyancy to a fish which may make it easier for them to swim, but many species of fish lack a swim bladder altogether. These include sharks
(which use an oily liver to maintain buoyancy), lampreys, darters, sculpin, hawkfish, and others which tend to "rest" on the bottom or objects in the water and only swim when necessary.

To see how all these work together, try this: http://pw1.netcom.com/~dhibsher/lwavwork...

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they flap their fins.

Unless they're lancelets who don't have fins, then they just start flexing their body.

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They have joints and muscles. Their brain wills its body parts to move and sends the message down its spine. The muscles respond.
And they...MOVE.

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some thing called "FINS" honey:)

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they swim

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they vary the movements of their fins depending on which direction they would like to move in. Thats all that you really need to know to be honest.
:)

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A swimming fish is relying on its skeleton for framework, its muscles for power, and its fins for thrust and direction.

The skeleton of a fish is the most complex in all vertebrates. The skull acts as a fulcrum, the relatively stable part of the fish. The vertebral column acts as levers that operate for the movement of the fish.

The muscles provide the power for swimming and constitute up to 80% of the fish itself. The muscles are arranged in multiple directions (myomeres) that allow the fish to move in any direction. A sinusoidal wave passes down from the head to the tail. The fins provide a platform to exert the thrust from the muscles onto the water.

Drag is minimized by the streamlined shape of the fish and a special slime fishes excrete from their skin that minimizes frictional drag and maintains laminar (smooth) flow of water past the fish.

Fish move up and down in the water with the use of a swim bladder. This swim bladder inflates to make the fish rise and defates to help him sink.

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I will give you a short and sweet answer..

Fish have air-filled sacs called swimbladders inside their bodies. A fish's swim bladder is one of its most unique and vital organs! Fish use this marvelous balloon to adjust their buoyancy, so that they don't have to work to maintain their floating level.

Fish move by creating a wave motion that moves the length of its body. This wave motion begins at the head and moves to the tale where the resulting side to side motion produces thrust to move the fish through the water.