What is surface agitation? Why is it so important?

Bloop. Bloop. I always wanted to know how my collection of goldfish can breathe in that tiny little fish tank. So, I researched aquariums and filtration systems just to see exactly how this was possible.

What is surface agitation? Surface agitation is the paramount element in ensuring the lifeline of the fish inhabiting your aquarium. The process fosters the key exchange between the oxygen entering the tank and the carbon dioxide exiting, which creates a breathable environment for your aquatic life.

Why is surface agitation so important?

Surface agitation is vital in the survival of your fish! Without surface agitation, your aquatic life will suffocate within their own environment. Fish need oxygen to survive, and surface agitation provides the necessary levels to ensure that they are receiving the right amount.

Can surface agitation be naturally produced?

Natural surface agitation can only be produced under natural circumstances. The rapid or slow movement of a pond, stream, or ocean typically provides the necessary levels of surface agitation for aquatic life to prosper. However, it terms of your home aquarium, water movements without the interference of an aerator or filer tend to be still, which increases the level of surface tension. The exchange between oxygen and carbon dioxide is always naturally occurring, but in a home environment, it is always necessary to further increase the rate of gas exchange to ensure the proper levels of oxygen being delivered to your fish.

How long does it take to produce surface agitation?

Surface agitation can occur within minutes. Typically, the moment air bubbles are introduced within your aquatic environment, surface agitation has already begun to occur. The longer oxygen is delivered to the tank, the faster and more efficient surface agitation can be produced.

Is surface agitation always necessary?

Surface agitation is always a necessity. Even though some aquatic environments contain plant life, which increase the levels of oxygen, the level of carbon dioxide also increases as well, which must be released for the sake of the aquatic life existing within breathable conditions. Surface agitation must always occur to further increase and maintain a healthy gas exchange between the surface of the water and the oxygen within the tank.


How do my collection of goldfish get air to breathe in that tiny fish tank?

I recently discovered that creating surface agitation is the key component. Surface agitation occurs by simply pumping air into the tank’s water. Utilizing some form of an aeration system, air must be pumped into the water until bubbles rise and burst at the surface. The consistent bursting of air bubbles immediately breaks the water’s surface tension, and thus surface agitation has occurred. This is also a useful element in evenly distributing the contents of the water in the tank as well. Evenly distributing harmful and beneficial matter and bacteria within the aquarium levels the contents of the water, which in turn make surface agitation easier and more effective.

Many aquarium enthusiasts often struggle with the correct method in inducing surface agitation. Often, it is difficult to determine which is most effective in forging sufficient aeration. There is no set standard setting for filtration nor aeration settings; users attempting the process of surface agitation often must observe and determine what best suits their aquarium’s environment.

Variations in the Source of Surface Agitation

The surface of the water in an aquarium is constantly undergoing an endless cycle of give and take. As oxygen is continuously drawn through the surface for fish to inhale, very similarly to us, they exhale carbon dioxide, which exits the surface as the oxygen enters. It is essential to constantly disturb the surface of an aquarium and increase the gas exchange at a sufficient level. This ensures that the aquarium inhabitants can maintain healthy breathing. Many aquariums are designed with a filtration systems integrated into their tank’s components that forge a strong cycle of surface agitation. For instance, numerous aquarium owners use permeable air stones connected to the filter’s air pump. When the air outside of the tank infiltrates the surface of the water, the filtration system forces the oxygen through one end of the stone, and the stone releases the oxygen, along with the gathered exhaled carbon dioxide from the fish, through the other side. Other filtration systems simply use air bubbles as a circulation method. In these models, air bubbles are forced to move in an upward direction pulling the water along with it. In turn, this creates a circular current, which cleans the water as well as creates sufficient surface agitation. A common misconception with regards to the air pump is that it must remain on the highest setting at all times. This is not accurate. Too much surface agitation can result in an excessive amount of carbon dioxide being released. Once there is an over abundance of CO2, the ratio between that and water reaches an inequality once more causing a strain in the fish’s ability to breathe freely. To reach the ideal setting, it is highly recommended that individuals monitor behavioral aspects of the aquarium’s inhabitants to determine the correct levels of surface agitation necessary. When fish are more active and don’t appear strained or as though gasping for air, the goal of preferred surface agitation has been achieved. Some fish also hate surface agitation i.e. Betta Spendin, which prefer the gentle movement of the water as common to what is found in their natural habitat. So, once more, it is necessary to evaluate and execute the proper surface conditions. Without the essential level of surface agitation, the ability for the bacteria in the water to breakdown organic matter will be ineffective. This will cause the combined effects of increased carbon dioxide and water creating carbonic acid. Oxygen levels will deplete along with the deterioration in the quality of the aquarium water, which can ultimately lead to your fish’s demise.

For more information, see https://animals.howstuffworks.com/pets/choosing-aquarium-equipment5.htm.

Horizontal and Vertical Surface Agitation

The horizontal method for surface agitation is far more superior than the vertical. Horizontal surface agitation tends to move the water around much more frequently resulting in greater reduction of surface tension. Vertical surface agitation, i.e. the bubble method, is generally only focused in one area as to where the oxygen bubbles burst on the surface. Horizontal is often the most common method of surface agitation chosen by aquarium owners, and it is achieved through simply aiming the power head connected to the filtration system in an upward horizontal manor.

How Plant Life Effects Surface Agitation

Live plants existing within your aquarium’s environment vastly affect the levels of surface agitation necessary. It is ideal to run horizontal or vertical methods of injecting oxygen into the aquarium during the nighttime, as there is a quantity of fish that must be taken into consideration. Plants undergo the process of photosynthesis during the day, which naturally can increase oxygen levels. It is recommended that oxygen pumps are utilized during the nighttime, to counteract the Co2 the plants are producing when the process of photosynthesis has reached the exhaustion phase. A combination of live plants naturally producing oxygen during the day and releasing Co2 at night combined with oxygen being pumped into the tank at night as well will most certainly create sufficient surface agitation.

Different Forms of Aeration

There are many forms of aeration systems that can effectively promote the healthy transfer of oxygen. Some of the more common methods are high speed surface aerators, fountains, and paddlewheel aerators. High speed surface aerators focus on mixing high volumes of water taking into account biological aspects of the aquarium such as plant life. Fountains pump and expel water into the air, rendering a blueprint for high efficiency air-water contact for the transfer of oxygen. The water propelled into the air breaks into tiny droplets, and when the droplets return the surface of the water within the tank, oxygen is transferred and dissolved back into the aquarium. Paddlewheels, very similar to fountains, also use an air to water method for the transfer of oxygen. Electronically powered paddles often are used to churn the water. Each time water is churned by the paddlewheel, oxygen is absorbed and returned back to the surface, hence forming the perfect surface agitation cycle.

For more information, please see https://www.wateronline.com/doc/aqua-lator-high-speed-floating-surface-aerators-0001

Determining the Correct Oxygen Levels for the Aquarium’s Inhabitants

The critical level of oxygen for fish often depends on the environment of the water and the fish itself. For instance, a goldfish can more than often effectively absorb oxygen into their tissue for greater than most, therefore, it is easier for them to withstand low oxygen conditions for a longer duration. Larger fish tend to use more oxygen than smaller fish as faster swimming fish tend to use more oxygen than slower ones. The temperature of the water also plays a substantial factor in the level of oxygen required as well. Because fish are cold blooded, there metabolisms respond cohesively with the rise or fall of temperature levels. The warmer the water, the more active the fish become, hence, the more oxygen that I required. However, warm water tends to hold less oxygen, therefore, it would become a necessity in this instance to increase surface agitation.

Please see https://www.tfhmagazine.com/aquarium-basics/columns/aeration-and-oxygenation.htm.

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