how to get rid of algae in fish tank naturally

Algae are a natural part of aquarium biocenosis. However, when overgrown, they do a lot of harm. To understand how to get rid of algae in fish tanks naturally, you need to have an understanding of the main varieties and their weaknesses. Caring for fish and aquariums is important.

Algae in the aquarium can form both as plaque on glass and turbidity in the water and in the form of formations on plants.

how to get rid of algae in fish tank naturally

what is aquarium algae?

Many novice aquarists refer to all aquarium vegetation as algae. This view is wrong. Plants growing in the aquarium are the highest representatives of the plant kingdom: ferns, mosses, and grasses. The lower forms of life belong to algae (algoflora).

This is a large heterogeneous group that unites unicellular, multicellular and colonial forms of living organisms that live mainly in the aquatic environment. Not all of them are plants.

They do not arise out of anywhere, but enter the container along with water, new animals, plant samples, food, stones, snags. In addition, spores of common species are always present in the air.

Algae in the aquarium can lead to plant death.

Under favorable conditions, their active growth begins, as a result of which:

  • the aesthetic appeal of the aquarium is disturbed;
  • plaque forms on the inner surface of the walls, the water becomes cloudy, green or yellow;
  • an unpleasant odor appears;
  • the filter is clogged;
  • plants and fish die.

Algal expansion indicates low water quality, imbalance in the biocenosis.

There are also useful species that are biofilters, substrates for spawning and viviparity, and shelter for fry. Some macroalgae are used in aquascaping.

types of aquarium algae

There are tens of thousands of varieties of algae.

types of aquarium algae

Common aquarium species:

  • diatoms;
  • brown;
  • green;
  • red (purple);
  • blue-green (cyanobacteria).

The choice of an effective way to control algae in the aquarium depends on their belonging to one of these taxonomic groups.

Most often, diatoms form in poorly lit aquariums and infect plants.


They are microscopic unicellular organisms covered with a silicon shell. Sometimes they unite in colonies. They are capable of secreting mucus. Most often they attach to various surfaces, forming dark green, yellowish or brown speckled growths that merge into larger formations. Often found in new aquariums. Develop well in low light conditions.

Getting rid of diatoms can be tricky. It is necessary to improve illumination, maintain the temperature at + 25 ° C, carry out a water change, clean surfaces, adjust the level of silicates (remove decorative stones, use a special filter).


They are often confused with diatoms, although they represent a separate class. These are flagellate organisms, one of the developmental stages of which is the multicellular form. They live mainly in the seas, but there are several freshwater species. Their color is determined by a brown pigment that overlaps other pigments.

They are found infrequently, mainly in young aquacenoses. They form a brown slimy coating on glass, stones, snags, decorative elements, and plants. The wrong choice of lighting can stimulate their development. Plaque is removed mechanically and with the help of live cleaners.


This division of lower plants includes both unicellular and multicellular organisms. A distinctive feature is the presence of chlorophyll, which provides a green coloration of cells. Most representatives lead an attached lifestyle only at the beginning of development, then they develop in the water column.

They appear in the form of point formations, a green film on the walls or bottom, threads, tangles. The optimal conditions for their development are high temperatures, long daylight hours, an abundance of carbon dioxide, phosphates and nitrates.


These are bacterial organisms capable of photosynthesis. The department of cyanobacteria includes unicellular, colonial, filamentous forms. Their color ranges from greenish to deep blue. They form a slippery green coating on glass, soil, plants, are the main cause of water bloom, emit a characteristic unpleasant odor, and alkalize the aquatic environment. Some species release toxins.

Blue-green algae are formed due to the general pollution of the water in the aquarium and an overabundance of lighting.

The active growth of organisms is caused by various reasons:

  1. Excess organic matter due to overfeeding of fish.
  2. The pH level is 7.5-9.5.
  3. Insufficient aeration.
  4. Intense lighting.
  5. Increase in water temperature.
  6. Excess phosphate fertilizers.

To suppress their activity, a set of measures is used, including mechanical cleaning, increasing the oxygen content, planting rapidly developing plants, using antibiotics and antiseptics.


Refers to green algae.

Main representatives:

  1. Cladophorus. It has a branched structure, reaches 2-3 cm in length. It is formed during stagnation of water and a lack of macronutrients.
  2. Edogonium. Appears in the form of a green cannon on leaves or ground, then gives long threads. It grows with a lack of macronutrients.
  3. Rizoclonium. Appears in recently launched aquariums as slippery, filamentous clusters of pale green color. The reason is the unsettled nitrogen cycle.

Spirogyra also has a filamentous structure, although it does not belong to green, but to harophyte algae. Its rapid growth is noted under strong light, an imbalance of mineral additives, and an excess of organic matter.

Better to remove the thread by hand. Its growth is suppressed by actively developing plants. 3-day darkening and the use of algicidal preparations are often practiced.


It is a type of red algae also called a black beard. It is a weakly branching rigid filamentous process up to 15-20 mm long. Their color ranges from black to dark green. They attach to aquarium cultures, grow into their epidermal cells as rhizoids, destroying the structure of the latter. Therefore, they need to be removed only together with the affected leaves.

Often, a black beard is confused with another red alga called Vietnamese (Audouinella species). It is slightly different in appearance: its soft reddish-brown or black filaments grow in small tufts. In foreign sources, this variety is called a black beard, and a pest of aquarium flora, which in domestic aquaristics is called a black beard, is called a deer horn in English-language literature.

Both varieties are very harmful and difficult to breed. It is recommended to reduce the intake of organic matter by reducing the number of fish, remove snails, turn off the devices that create the flow, maintain cleanliness, often change water, and increase the supply of carbon dioxide.

Algae from the order Compsopogon are often called “beards” because they grow in a dense bunch.

How To Get Rid Of Algae In Fish Tank Naturally?

The fastest and most stable results are obtained with the complex use of various methods.


Most algae require high illumination. Therefore, aquariums should not be placed on windowsills, in front of windows or in other places where direct sunlight falls for more than 2 hours a day.

Lighting in the aquarium in the evening can cause algae to appear.

A reduction in the length of daylight hours to 8 hours on ornamental plants is not strongly reflected, and for unwanted growth it often becomes destructive.

Sometimes the light is removed completely for several days by installing a compressor to supply oxygen to the fish, since plants do not perform this function in the dark. This approach is effective, for example, when water blooms.

The light intensity should be moderate, the norm is 0.5 W per 1 liter. An excess of light provokes the appearance of green algae, and a lack of it – brown and diatoms.

In some cases, it is necessary to select lamps depending on the spectrum. For example, blue light (600 nm wavelength) is temporarily used to combat a black beard.

The stepped lighting method has proven itself quite well. While maintaining the usual length of daylight hours in the morning and in the evening, you need to reduce the intensity of the light flux by half.


There are many animals that feed on algae.

Otozinklus affinis fish feed on algae and cleanse the aquarium.

Among fish, preference should be given to:

  • Siamese algae (Crossocheilus siamensis, Epalzeorhynchos siamensis, SAE), their Indian counterparts (IAE);
  • Otocinclus;
  • swordtails, guppies, mollies and other members of the Poeciliidae family;
  • Jordanella (Jordanella);
  • gastromizones (Gastromyzon);
  • trophies (Tropheus);
  • hypostomus (Hypostomus).

Some fish may switch to ornamental greens.

This is typical for varieties such as:

  • girinoheilus (Gyrinocheilus aymonieri), they are also called Chinese algae eaters, or KAE;
  • catfish-ancistrus (Ancistrus);
  • pterygoplichthys (Pterygoplichthys), etc.

Other animals can be used to clean algal growths on various surfaces. Bivalve molluscs or a large group of daphnia can help with flowering water. Many species of algal flora are handled by the Amano shrimp (Caridina multidentata, the outdated name of C. japonica). They will also help cleanse velveteen ball colonies from rapidly appearing dirt, returning them to their former decorative appeal.

At the initial stages of the outbreak, you can use snails (ampulla, coils, theodoxus, etc.). But with severe lesions, they are not always effective.


In the aquarium, there is a struggle for light, carbon dioxide, nutrients, mineral supplements. Here, the algoflora loses to the intensively developing aquatic grasses.

To combat the algal population, fast-growing long-stemmed varieties are used:

  • ludwigia;
  • hygrophils;
  • vallisneria;
  • nayas;
  • rotals, etc.

Plants do not need to be planted, floating forms such as hornwort, pistia, elodea, etc. can be added.

Feeding herbs with organic and mineral supplements should be strictly dosed.

Ludwigia (left), Hygrophilia (center), Vallisneria (right) can fight algae due to their rapid growth, which requires a lot of nutrients that the algae will lack for development.


Increasing the supply of carbon dioxide enhances plant growth, which leads to inhibition of algal activity. Its approximate level is 10-20 mg / l. The required concentration is selected individually. It should not be critical for the species of fish available. At the same time, it is necessary to maintain a constant pH level and make sure that its value does not fall below 6. If there is no ornamental vegetation or it is poorly developed, the supply of carbon dioxide must be stopped.


Hydrogen peroxide (3%) is added to water at the rate of 1.5-2.5 ml per 10 liters.

It is a superoxidant used to fight cyanobacteria, black beard and Vietnamese. A solution of 3% is used at the rate of 1.5-2.5 ml per 10 liters of water. It is better to inject it with a syringe without a needle in the place of accumulation of unwanted growth.

The affected leaves are removed first. Apply the product with caution in combination with other measures.


Used for disinfection of containers, water, decor, equipment. It can be Whiteness, bleach solutions 5% or chloramine 3%. Consideration should be given to their negative impact on microflora, plants and animals. Chlorine is volatile, released from water during settling. You need to wait at least 1-2 days. You can use special means to quickly remove it.


An excess of organic matter creates favorable conditions for the development of algal flora. Most of the nutrients are concentrated in the water due to overfeeding of fish. To reduce the content of organic compounds, live or frozen food should be given, and its portion should be limited to the necessary minimum.

At the same time, frequent water changes are carried out (2-3 times a week at least 20% of the volume), maintain cleanliness. Excess nitrogen and phosphorus are removed with special additives such as Aqua Medic antiphos or Tetra NitrateMinus Pearls.


This compound exhibits disinfecting properties. It decomposes in water within 24 hours with the release of carbon dioxide. In the fight against black beard and antler, it is more effective than other means, does not affect spores.

Glutaraldehyde is a disinfectant that can be added to water.

This component in a concentration of 2.5% is included in various preparations:

  • Sidex;
  • Aquayer Algicide + CO2;
  • Professional Algae Killer;
  • ZMF Algo stop fix etc.

Before use, experts recommend removing visible foci of infection and siphoning the soil as much as possible. The dosage for prophylactic treatment of a volume of 100 liters is 3 ml, with a weak infection – 5 ml, pronounced – 10-12 ml.

This amount is relatively safe for long-term use. In advanced cases, a double dose is administered briefly or once. In this case, it is desirable to increase the aeration.

How To properly clean aquarium from algae?

The frequency of the procedure depends on several factors:

  1. The size of the aquarium. Containers with a volume of 10-20 liters must be cleaned weekly, from 100 liters at least once a month.
  2. The number of animals. The more there are, the faster the environment becomes polluted.
  3. Balancing biocenosis. If the balance is out of balance, cleaning has to be done more often.
  4. Correct care. Content errors also cause rapid contamination.

This is a planned purification with a partial water change. The aquarium is rarely completely washed, no more than 1 time in several years, since the established biobalance is disturbed. This is also done before a new start and, if necessary, a thorough disinfection of an existing aquarium.

A special scraper is used to clean the aquarium glass, and the decorative elements must be cleaned by hand and disinfected in glutaraldehyde.

Planned works include:

  • cleaning the walls with a scraper or washcloth;
  • cleaning of decorative elements;
  • trimming and thinning vegetation;
  • soil siphon;
  • rinsing filters in aquarium water;
  • wiping lamps and cover glass;
  • removal of 15-30% of the water volume with replacement by the corresponding amount of fresh settled water.

Processing of gravel, decor, equipment, plants is carried out as needed. No detergents or cleaning agents are used. Before starting the procedure, you must turn off all electrical equipment with the exception of external filters, and then do not forget to activate it again.

Deep (thorough) cleaning requires a complete system restart. The algorithm for performing the work is preserved. Fish and other animals are placed in temporary housing. Do the same with plants. Take them out carefully so as not to damage the roots. The soil is heat treated or replaced with a new one. The container is washed with a disinfectant, then dried for at least 24 hours. It is better to boil the inventory.

how to prevent algae spread in aquarium

The main methods for preventing the appearance of algae include the following:

  1. Placing the aquarium in a suitable place, no excessive light.
  2. Creation of optimal conditions for the growth of grassy crops.
  3. Standardized use of mineral fertilizers, correct proportions of micro and macro elements.
  4. Regulation of the amount of feed. Fish should eat it completely.
  5. Maintaining cleanliness. It is necessary to remove plaque from glass, stones, figurines, remove dead plant parts, and avoid excessive silting of the bottom.
  6. Compliance with the temperature regime. Water should not be warmer than + 24 … + 26 ° С.
  7. Correction of pH by regulating the supply of carbon dioxide.
  8. Preservation of biological balance, including bacterial, in an artificially created biocenosis.
  9. Inspection of vegetation for the presence of infection, timely adoption of appropriate measures. Quarantine of new samples of plants and animals.
  10. The use of algae eaters to control the algal population.

The complex of these measures will avoid the need for the use of chemicals.

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