how do fish breath ?

Answer 1

Fish breaths through gills.

Answer 2

How in the heck can a fish, which is underwater, breath if there is no air? When we go under water, we have to bring air with us to survive. Whales and dolphins have lungs that store air from the surface. Fish don't have lungs, and they rarely ever venture into the air, so how do they survive. We all know it has something to do with gills, but what exactly.

The water surrounding a fish contains a small percentage of dissolved oxygen. In the surface waters there can be about 5 ml. of oxygen per liter of water. This is much less than the 210 ml. of oxygen per liter of air that we breath, so the fish must use a special system for concentrating the oxygen in the water to meet their physiological needs. Here it comes again, a counter current exchange system, similar to the one we found in the fish's swim bladder and in the tuna's muscles.

The circulation of blood in fish is simple. The heart only has two chambers, in contrast to our heart which has four. This is because the fish heart only pumps blood in one direction. The blood enters the heart through a vein and exits through a vein on its way to the gills. In the gills, the blood picks up oxygen from the surrounding water and leaves the gills in arteries, which go to the body. The oxygen is used in the body and goes back to the heart. A very simple closed-circle circulatory system.

The gills: the gills are composed of a gill arch (which gives the gill rigid support), gill filaments (always paired), and secondary lamellae, (where gas exchange takes place).

* The blood flows thorough the gill filaments and secondary lamellae in the opposite direction from the water passing the gills. This is very important for getting all of the available oxygen out of the water and into the blood.
* If the blood flowed in the same direction as the water passing it, then the blood would only be able to get half of the available oxygen from the water. The blood and water would reach an equilibrium in oxygen content and diffusion would no longer take place.
* By having the blood flow in the opposite direction, the gradient is always such that the water has more available oxygen than the blood, and oxygen diffusion continues to take place after the blood has acquired more than 50% of the water's oxygen content. The countercurrent exchange system gives fish an 80-90% efficiency in acquiring oxygen.
* When fish are taken out of the water, they suffocate. This is not because they cannot breathe the oxygen available in the air, but because their gill arches collapse and there is not enough surface area for diffusion to take place. There are actually some fish that can survive out of the water, such as the walking catfish (which have modified lamellae allowing them to breathe air.
* It is possible for a fish to suffocate in the water. This could happen when the oxygen in the water has been used up by another biotic source such as bacteria decomposing a red tide.



How do fish ventilate their gills? Fish must pass new water over their gills continuously to keep a supply of oxygenated water available for diffusion. Fishes use two different methods for keeping a continuous supply of new water available, one is very simple and the other complex.

--Ram Ventilation: Swim through the water and open your mouth. Very simple, but the fish must swim continuously in order to breathe, not so simple.

Answer 3

Fish have gills that have structures called rakers, filaments that come in contact with water and extract oxygen from the water. That oxygen is then passed to the fish's blood by the capillaries and blood vessels and circulated through the body of the fish.

Some fish, such as Bettas, have a primitive lung like apparatus that is called a labyrinth organ witch allows them to extract oxygen directly from the atmosphere. This allows them to be kept in a very small amount of water without suffocation.

Kev

Answer 4

Most fish breathe through their gills. Water goes in through the mouth and passes through the gills. where oxygen is extracted from the water. Some types of fish come to the top and suck in air,and store the oxygen,and come up for more when needed.
Some of the earlier answerers gave enough details. I only summed it up.

Answer 5

Fish have gills, which are kinda like human lungs. The gills filter the water and extract the oxygen in the water. This is why it is important to aerate the water with an air stone, splashing water etc as well as water changes. To keep the water well oxygenated so it is easier for the fish to breathe. (to put it simply)

Answer 6

Well to put it as simple as possible they suck water in through their mouth which rushes out their gills, their gills work the same way our lungs work just they look different. And a good thing about fish is they can stop and still be able to breath, but sharks can't because of their gills are different, and yes some sharks stay still but they position themselves in currents so water rushes past their gills without moving

Answer 7

One of the things that make most fish very different from higher animals is the lack of lungs. Lungs is the place in animals where respiration occurs. The exchange of breathable air.

Fish obtain oxygen over the gills. Water, which contains diffused oxygen under pressure, passes over the gill filaments. A pressure gradient exist, allowing the exchange of oxygen in the water with co2 leaving the gill filaments. These filaments are very much like the ones humans have in their lungs, lamellae. They are thin tissue containing co2 laden blood.

Answer 8

They breathe through the gills. They don't have lungs though. Fish use their gills to extract the oxygen from the water they live in. Kind of complicated if you don't really know whats going on.

Answer 9

They suck in water into their mouth, which passes over its gills which takes the O2 out of the water.

Some labyrinth fish can store O2 in a special organ called a labyrinth (bettas and gouramis). They suck this directly out of the air.

If you don't have enough dissolved O2 in your water, fish may suck the water near the surface, which has more O2 in it. They are not breathing water from the air like a labyrinth fish can.

Answer 10

fishes breathe through their gills. oxygen is present in the water
so the fishes take in diluted oxygen and breathe