How to eliminate cyanobacteria in the aquarium?

How to eliminate cyanobacteria in the aquarium? Cyanobacteria are an aquarist's nightmare. For good reason, their development and their proliferation within an environment release highly novice cyanotoxins which end up suffocating an aquarium .

Cyanotoxins are possibly dangerous for the fauna of an aquarium. They become deadly when they form deposits above the aquatic flora because they prevent any chlorophyll activity in the latter.

The presence of cyanobacteria generally causes great damage within an aquarium. In freshwater or seawater, cyanobacteria terribly affect the morale of aquarists, because they are difficult to eradicate because of their resistance and their mode of reproduction. The usual cleaning techniques are generally ineffective in removing them. A small fragment is enough for cyanobacteria to reform a thick biofilm.

Appearance of cyanobacteria

Also known as blue-green algae or slimy red algae, cyanobacteria behave both like bacteria and like algae. They can have a reddish-brown or blue-green appearance. They most often appear very slowly in the form of small clumps or spots. Afterwards, they propagate and spread very quickly until they cover an entire aquarium. If you notice the presence of cyanobacteria in your aquarium, you must quickly establish eradication plans to eliminate them immediately. But also to prevent them from growing in the future.

Origin and description of cyanobacteria

Cyanobacteria are very ancient living beings that began to exist since the Precambrian in very simple forms. Clearly, their existence began 3.8 billion years ago in less complex forms than today.

The presence of cyanobacteria is even supposed to have favored the existence of certain forms of life on earth in the Precambrian. Forms of life of which we have no fossils. There are more than 7500 cyanobacteria which are divided into more than 150 genera.

Cyanobacteria have the ability to live in almost any environment whether on dry land, in fresh water or in sea water. Generally considered to be algae, cyanobacteria are actually bacteria. They do not have a cell nucleus and they are particularly capable of fixing nitrogen from the atmosphere.

This ability to fix nitrogen is however not possible for a plant or an algae. For cyanobacteria, this ability to fix nitrogen facilitates adaptation to any environment. Cyanobacteria reproduce only by bipartition by separating into two identical parts which will lead lives independent of each other.

The causes of the presence of cyanobacteria

Cyanobacteria generally have causes of varied and diverse origin. Cyanobacteria are most commonly caused by:

• An aquarium that is insufficiently or ineffectively maintained (eg water that is not changed regularly)

• The decomposition of all organic waste from plants (dead leaves, stems, branches, etc.) in the water of an aquarium

• An aquarium water excessively rich in nitrogenous compounds which results from the dissolution of organic matter and which nourish cyanobacteria

• Often unsuitable food remains that pollute the aquarium water (food given to animals in too large quantities)

• Decomposition of dead fish within aquarium water

• The high temperatures and the basicity of the water which accelerate their development

• The infiltration of copper within the aquarium water which is due to the use of antibacterial drugs and treatments

• Lack of oxygen supply • Insufficient mixing at the surface

• Poor water circulation due to the existence of dead zones within an aquarium

• The imbalance of the NO3/PO4 ratio It should however be noted that cyanobacteria are living beings which are always naturally present in an aquarium.

Cyanobacteria are therefore never missing. They just wait for the water in the aquarium to be unbalanced to proliferate. Also, cyanobacteria feed on nitrogen. They therefore tend to appear when the water in an aquarium becomes rich in nitrogenous matter.

Anticipating the appearance of cyanobacteria is very complex. For good reason, even in clean aquarium water (without nitrate and without phosphate) cyanobacteria are able to develop by first feeding with organic phosphate.

Consequences of the presence of cyanobacteria in an aquarium

The effects of cyanobacteria on an aquarium's water and population are always devastating if proper measures are not taken to control these cyanobacteria. As said a little earlier, when cyanobacteria propagate in an environment they release cyanotoxins.

These cyanotoxins are potentially dangerous, even fatal for the fauna and flora of an aquarium. The proliferation of cyanobacteria can smother the entire ecosystem of an aquarium.

Treatments against cyanobacteria

To eradicate cyanobacteria, it is better to first destroy manually and as far as possible most of them. To do this, you need to siphon them off every day. Clearly, you must siphon off all the smallest bits and you must very carefully clean the ground and the decorations which are contaminated.

Also, to fight against cyanobacteria you must assiduously perform certain operations which are:

• Perform partial water changes frequently as soon as the aquarium water becomes too rich in nutrients conducive to the development of cyanobacteria.

• Rid the aquarium water of organic debris (dead leaves, stems, remains of animal food, etc.)

• Rid the aquarium tank of excess cyanobacteria clinging to it, in particular by scraping it with scrapers or with other tools available in pet stores.

• Carefully clean the filters frequently

• Use a protein skimmer in your aquarium. (one of the major factors of cyanobacteria is the presence of organic debris, namely dead leaves, food scraps, fish waste, etc. in the water column). Protein skimmers can be more effective than regular filters when it comes to removing these organic debris from aquarium water.

• Limit the amount of food given to fish, avoiding excesses (because leftover food contributes greatly to the rise in phosphate levels in aquarium water)

• Add aquatic plants to your aquarium that will not only feed on the same nutrients as cyanobacteria. But also which will share sunlight with cyanobacteria.

• Limit your aquarium's exposure to light, as while light is essential for aquatic plants, it can also create an environment that promotes the growth of cyanobacteria

• Check the quality and intensity of the lighting

• Check the quality of your tap water

• Test the pH of your tap water

• Improve water movement within your aquarium

• Improving maintenance Still with a view to eradicating cyanobacteria, one of the methods that are commonly used is the general blackout.

The blackout boils down to depriving the aquarium and all its occupants of light by plunging the aquarium into total darkness for a minimum of 4 days. This method of fighting cyanobacteria has been shown to be effective for some people. You can also try the blackout if the plants in your aquarium are not fragile. Otherwise, the absence of light will certainly reduce the development of cyanobacteria, but it will inevitably cause a disaster among your plants. Sometimes, to counter the spread of cyanobacteria, a simple rebalancing of the good bacteria can be more than enough.

To add live bacteria to your aquarium, you can obtain bacterial preparations which are generally available in stores or pet stores. Water quality can also be the basis for the development of cyanobacteria. For example, a low nitrate level favors the multiplication of cyanobacteria. For this reason, you need to check the concentration levels of your aquarium water. You must specifically ensure that nitrate levels are maintained at reasonable levels of 5 to 10mg/L.

To achieve an increase in nitrate levels in your aquarium water, you can choose solutions that are available in pet stores or shops. The development of cyanobacteria can also result from the NO3/PO4 imbalance (Redfield's report). If the nitrate level of your aquarium water is below 5 mg/L, you have the option of adding KNO3 (potassium nitrate) and PO4.

The Redfield report recommends respecting the ideal ratio between nitrate and phosphate, i.e. 10 mg of nitrate/litre for 1 mg of phosphate/litre. An imbalance in this ratio can favor the development of cyanobacteria. The use of copper sulphate can also help you fight against cyanobacteria.

For good reason, copper sulphate is very harmful to cyanobacteria. However, it can also be a poison for certain elements of the fauna and flora of an aquarium. The use of chemicals to eradicate cyanobacteria is strongly discouraged.

The use of antibiotics to fight against cyanobacteria is therefore recommended as a last resort. It should be noted that if you have several aquariums and you are contaminated by cyanobacteria, you must take care not to use the same cleaning materials for your aquariums.

In short, a miracle solution to eradicate cyanobacteria unfortunately does not exist. Instead, the aquarist is advised to look for the specific causes of cyanobacteria. He can therefore remove the problem from the database.