Do Fish Need Oxygen? Here's What Low Oxygen Can Do To Them | Kidadl

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Do Fish Need Oxygen? Here's What Low Oxygen Can Do To Them

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You might have seen fish coming to the surface of the water regularly.

It might have occurred to you that they are breathing oxygen in the air. But are they really intaking oxygen?

Having a fish tank with fish and little aquatic plants does really get our attention. But do you know the fish tank needs proper maintenance? Have you ever thought about why it is so? A lot of it comes down to fish and oxygen. Much like humans, oxygen is a vital part of the fish's life. How so? Do fish need oxygen? What happens when there is low oxygen, do they die? Let us find out the answers to all these questions and understand how fish need oxygen and how do they get it. After reading about if there is a need to increase oxygen in fish tank for the fish to breathe, also check do fish have eyelids and do fish have livers?

Do fish need oxygen?

Human beings cannot survive without oxygen. We need oxygen to survive. Are we the only species that need oxygen to live a life? Obviously not. Almost every species in the world needs oxygen. Yes, that's right. How about fish? Do fish need oxygen? Simple answer? Yes, they do. Fish need oxygen to live.

Fish need oxygen to breathe. Just like humans use oxygen in the air to breathe, fish use oxygen in the water to breathe. If you have a pet fish in the aquarium, you should know that they breathe in oxygen through the water. But the fish is not the only one that takes up oxygen from the aquarium. The plants and filter bacteria inside the aquarium also need oxygen. The plants inside the fish tank need oxygen to live. If there is low oxygen in the aquarium, the plants will eventually die. Similarly, the filter bacteria need oxygen to break down ammonia to less harmful nitrates.

If the filter bacteria cannot find enough oxygen to do so, the bacteria cannot complete this task. We don’t even have to emphasize what will happen if the fish does not find enough oxygen in the water. The lack of oxygen will eventually cause their death. Oxygen is important for the respiration process and a critical supply of energy. Even so, the amount of oxygen that each species of fish needs will be different from each other. Some fish species can survive with less oxygen compared to others. But still, it doesn’t change the fact that oxygen is critical for a fish.

It is related to their breathing process and the availability of oxygen could help in the healthy life of the fish. The main difference in fish is that, unlike humans, they breathe oxygen through the water instead of air. If the water contains low oxygen levels, then it could seriously affect the breathing of the fish. not just the fish but also the plants and bacteria in filters. The whole aquatic life will have problems without oxygen.

As per research by Duke University, air pumps are not a necessity for aquariums as fishes can survive forever without an air pump. In completely still water, fishes may survive for two days and if a filter is installed for surface water movement, the air pump is rendered unnecessary.

How do fish obtain oxygen?

Now, we know that fish need oxygen, how do they get this oxygen? We have already mentioned how they breathe in oxygen from the water, but how do they do it? We know humans have lungs to get oxygen into the body. To breathe oxygen into the body, fish have gills.

The gills of a fish does the job of the lungs in humans. The oxygen in water is more compared to the oxygen in the air. When water passes through the mouths through gills on each side, the absorption of oxygen from water takes place. The dissolved oxygen is taken into the body of the fish and the carbon dioxide is released into the water too. The dissolved oxygen moves into the fish’s cells through the blood.

The blood moves throughout the body to deliver this oxygen. In humans too, the blood moves throughout the body carrying oxygen. In that sense both of these species are similar. Even when you know this, a doubt may arise in the mind. Why do some fish come to the surface of the water often? You might have often seen dolphins and whales swim to the surface of the water from the ocean to breathe. Why is it so? To state the obvious, dolphins and whales are mammals. They are similar to humans in many factors. They breathe in oxygen through the air. In order to do that, dolphins and whales need to come to the surface of the water.

While fish get oxygen from the water, mammals in the water tend to get oxygen from the air. Breathing in oxygen through the mouth is hard for a fish due to the high amount of dissolved oxygen in the water. When it comes to fish in a tank, the fish get oxygen from the aquarium water although there is a chance for the dissolved oxygen in the aquarium water to be depleted after some period. Wherever they are, fish get the oxygen they need through the water they live in.

Various articles and news regarding fish requiring oxygen for breathing are enjoyed by everyone.

How long can fish go without oxygen?

What happens if the dissolved oxygen in the water decreases? The fish usually dies. But how long can the fish hold on in the water before it dies? In other words, for how much period of time can they hold out without oxygen?

This concern would especially arise in the case of aquarium fish. It is possible that the fish tank could experience a power outage. During this period, all the factors of the aquarium tank and its function will stop. The circulation of water will not happen. For the circulation to happen the water needs to reach the air-water interface. This means that the fish has to survive in the oxygen levels left in the aquarium.

It would mainly depend on the number of fish in the tank along with some other factors like the condition of water and the species of fish. For example, fish like goldfish can survive for almost five months without oxygen. But this is not the general case. In terms of aquarium fish, it will be hard for them to survive more than two days without oxygen. If there are too many fish in the tank, there will not be much oxygen left for everyone. The saturation of oxygen in water depends on the temperature and salinity of the water.

When you increase the temperature and salinity of water, the amount of saturation of oxygen gets lower. Both the temperature and salinity should be maintained at a level that will create the maximum oxygen saturation in water, enough for the fish to survive in case of an emergency like a power outage. A low oxygen level can also be due to various other reasons. If the plants in the aquarium have a short light period, this can lead to low dissolved oxygen. The plants will produce oxygen during the light period and will also use up the oxygen at the night.

If the plants get more light periods for photosynthesis, they will be able to produce more oxygen. If the amount of filter bacteria in the tank is high, it can also lead to a depletion of dissolved oxygen in the water. Apart from maintaining an adequate water temperature, you can increase oxygen in fish tanks by making necessary changes in terms of plant light time for photosynthesis and the number of filter bacteria.

What happens when there is low oxygen in a fish tank?

The answer is quite simple. Depending on the species of fish in the tank, they can either die or start gasping for oxygen. But wait there's more to it.

When the oxygen levels in an aquarium tank decrease, a fish will start to push water through the gills. It is the way of gasping for them. At other times, they will come to the surface of the water to get oxygen. The surface of the water would comparatively have a higher concentration of oxygen so to get maximum oxygen into the body, they will start to move to the surface. If you ever found your fish on the surface more often, it is a sign of the oxygen levels being low in the tank. Even though the plants in tanks like algae produce oxygen, the oxygen levels can still get low.

Algae can only produce oxygen in the daylight. During the night, they also need oxygen to survive. In the same way, bacteria also need oxygen to convert ammonia to nitrite. All these factors together contribute to the low oxygen levels. At the same time, signs of too much oxygen in a fish tank can lead to gas bubble disease in fish too. In this disease, gas comes out of the fish solution creating bubbles all over its skin.

It is important to have a proper water temperature in the fish tank. Apart from some cold-water fish species, all other fish prefer warm water. It is important to have a proper warm water temperature along with oxygen levels for the healthy maintenance of the fish.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for do fish need oxygen then why not take a look at do fish have tongues, or do fish have blood?

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Kidadl Team

The Kidadl Team is made up of people from different walks of life, from different families and backgrounds, each with unique experiences and nuggets of wisdom to share with you. From lino cutting to surfing to children’s mental health, their hobbies and interests range far and wide. They are passionate about turning your everyday moments into memories and bringing you inspiring ideas to have fun with your family.

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