How Do Fish Breathe

Surely more than once you have wondered how fish breathe. If so, you have come to the right place. The truth is that fish are very interesting animals, and their breathing is a process truly worthy of study.

In the event that you are someone who wants to start an aquarium, this information will be very valuable to you. In order to ensure that your fish breathe well in their aquarium, you need to understand how their respiratory system works. Only knowing how the fish breathe is that you will be sure that you meet their needs and that they will not die in the process.

For this reason, today we will try to clarify all your doubts about how fish breathe.  We will also give you some tips so you can make sure that the fish in your aquarium can breathe properly. Keep reading and find out everything you need to know about the first vertebrates that appeared on earth and their breathing. As a bonus, you will learn a couple of things that you may not have known about the respiration of other animals.

Different ways of breathing in animals

Respiration is a vital process in which oxygen is extracted from the air or water in order to release carbon dioxide. The importance of a respiratory system in animals lies in the high number of cells that most have. Its function is to collect as much oxygen as possible to distribute it in the cells of the body, so that everything can function properly.

There are some animals, however, that are simple in structure with few cells. These do not need a respiratory system to survive, as they can exchange gases without major complications. An example of these animals is flatworms or sea sponges.

Now that you know this, let’s take a look at a few forms of respiration in the animal kingdom. Surprisingly, animals have more than one way of breathing, there are even some that differ greatly from ours. Here are some of them.

Tracheal breathing

This is how insects, myriads, and a small group of arachnids breathe. The air from outside the animal connects with the cells of the entire body through the tracheae; and the tracheas are a kind of cylindrical structure. These cylinders open to the outside through holes that can be closed with the help of spiracles.

The circulatory system is not part of this respiratory system. This means that it has nothing to do with transporting oxygen to cells. This is because this type of animal tends to have an open circulatory system. In such a circulatory system, the blood does not move fast enough to provide a high level of oxygen. In fact, the oxygen it provides is not enough to make rapid movements like those of these animals.

Cutaneous respiration

Cutaneous respiration is used by creatures such as mollusks, amphibians, annelids  (type of worm), and some echinoderms. In the case of amphibians and mollusks, it is common that they need to complement this system with other respiratory systems.

Cutaneous respiration is based on the skin, which is responsible for carrying out the gas exchange that respiration entails. Which leads us to the conclusion that the body integument is the respiratory structure of this system? For the correct performance of this respiratory system, the animal’s skin must be extremely thin and remain moist.

Lung breathing

As the name implies, pulmonary respiration depends on the lungs. Mammals, birds, reptiles and a selected group of amphibians are those that have this type of respiratory system. Different structures and degrees of evolution can be seen in the lungs depending on the species.

There are two types of lungs; there is the secularlung, with a sac-like image, which mammals and reptiles possess; and the tubular lungs, in the form of tubes, attached to air sacs that only birds possess.

Instructions for breathing fish

Let’s get to the good stuff, let’s see now how fish breathe. You see, water, in contrast to air, has lower oxygen content. To extract the small amount of this element that is in the water, the fish use their gills; from them they take the oxygen necessary for their respiration. This means that fish have a bronchial respiratory system.

The gills are located between the mouth and the pharynx, and they only work with liquid. Thanks to this, the fish cannot be out of the water. When the fish opens and closes its mouth, water enters through the gills, pressed by the tongue. Next, the blood vessels are activated and take care of sending the collected oxygen to the blood.

The gills are found internally or externally, depending on the type of fish. The internal ones are more evolved than the external ones, since they are more protected inside. The gills are supported and can be moved by gill arches, protected by the opercula.

In bony fishes there are four gill arches, but sharks and rays can have four, five or six depending on how they evolved. The lower the evolution, the greater the number of arcs.

There are also fish with a less complex respiratory system. They must keep their mouth open for a longer time so that oxygen can successfully reach the blood. This is the case with tuna. It is important to note that the fish does NOT extract oxygen from the water. What it does is extract oxygen from the air dissolved in the water.

A very important factor in reference to how fish breathe is the temperature of the water. The warmer the water, the less oxygen it will have. This is the reason why some fish are only found in cold waters, because they need a lot of oxygen to survive. However, some fish can make a physiological adaptation. They increase the surface of their gills when they are in places with lower oxygen levels.

What do you need to breathe fish?

• Gills
• Lungs.
• Oxygen.
• Water.

Tips for fish breathing

Not only the fish, but also the plants in an aquarium depend on the oxygen in the water. They need it to live and to fulfill their biological needs. Therefore, it is very important that you check that your aquarium meets the needs of your fish and plants.  Don’t worry; here are some tips to make sure the way your fish breathe is correct.

1. Keep the aquarium clean. The body of the fish has a myriad of bacteria. These bacteria end up producing ammonia and charging the water with it. Add this to algae blooms, poop buildup, and other factors and you’ll see just how much waste your aquarium can have. All this will negatively affect the breathing of the fish, so you should regularly sanitize the aquarium. The ideal is to clean the aquarium every 15 days and the filter once a month, at least. Keep in mind that this can vary depending on the elements you have in your aquarium.
2. Always keep in mind the temperature of the water. Above we told you that the temperature affects the oxygen level and therefore the breathing of the fish. For this reason, experts recommend having a heating system in the water to prevent the outside temperature from affecting the water and the fish.
3. Use an aerator. The basic aerator consists of a pump, a hose and a diffuser. This produces a large number of bubbles that gives the fish oxygen in an indirect way. The current that the aerator generates distributes the oxygen evenly and will favor the breathing of the fish.
4. Make sure there is movement in the water. The movement is important for the correct breathing of the fish. If there is no movement, this will lead to poor oxygenation and can promote the concentration of toxins. The speed or strength of the movement will depend on the type of fish that live in the aquarium.
5. Learn about the respiratory needs of your fish. The respiratory needs of your fish can vary depending on their type. For this reason, it is best to consult an expert or ask about it at the time of purchase. Thinking that all fish have identical breathing is a mistake, as you could learn above.
6. Check your fish regularly. You should pay attention to possible signs that may indicate that your fish are not breathing as they should. If your fish show spots or changes in color, you should seek immediate help.
7. Fish can suffer from hypoxia(lack of oxygen) for the smallest reasons. Such as the increase in temperature or a chemical imbalance in the water. Prevent them from dying from this by checking them frequently.
8. Having an aquarium at home is very good in more ways than one. It’s decorative, it relaxes, and fish are very interesting creatures. For this reason, you must give them the attention and care they deserve. Being aware of your oxygenation is a key factor in your care and should not be underestimated.
9. It is a mistake to think that just putting the aerator on full is enough, because the breathing of the fish is much more complex than that. However, we know that you will do an excellent job with your fish if you follow this guide to the letter.

We hope you have learned a lot about animal breathing and how fish breathe. If you dare to make your own aquarium, we wish you the best of luck and we hope you enjoy your fish and its care.