How to Get Rid of Freshwater Aquarium Planaria (Flatworm)?

You may have seen these little worms crawling on aquarium glass. It is true that they cause a bad image in the aquarium. So what are the causes of planaria infestation, and how can you get rid of planaria? Are planaria harmful to fish? Is it harmful to humans? Detailed information about planaria can be found in our article.

What Are Planaria?

Planaria, the class of flatworms, belong to the order Turbellaria. It is possible to come across aquariums with a height of a few millimeters to a few centimeters. They have no swimming ability. Micronic eyelashes located under the abdomen perform a kind of foot function. Their digestive system is quite different from the usual structure.

The entrances of the digestive and excretory systems are under the abdomen. Their assimilation of the nutrients they take is accompanied by the movement of their bodies. They can reproduce sexually and asexually. Regeneration is very advanced. Even when they are divided into dozens of pieces, each piece renews itself and survives as an adult.

How Did Planaria Get in My Fish Tank?

Planaria are seen in aquariums as a result of the increase in the amount of organic waste. In aquariums that are neglected, the food residue remaining at the bottom is one of the biggest reasons for planaria infestation. Most of the planaria seen in aquariums are carnivorous. Protein-based feed residues are a major factor in planaria infestation. In regularly maintained aquariums, if rock-like heavy mass decorations are present, residues on rock bottoms that fish cannot reach may trigger the planaria infestation.

Another factor is that dead fish are not removed from the aquarium environment. It is difficult to find a dead fish, especially in a densely planted aquarium. As long as it does not move away from the aquarium, it rapidly decreases the water quality and is the main reason for planaria infestation. From this point of view, planaria infestation is a serious clue that water conditions are deteriorating. In insufficient filtration, it triggers the planaria infestation. If sufficient biological cleaning is not possible, it is possible to see these planaria even if there are no residues collected at the bottom.

How to Identify Planaria?

It is possible to select all the details under the microscope. However, it is more important how we distinguish these creatures under normal conditions. Planaria need a surface that they always have to hold onto for movement. Therefore, it is possible to appear on the floor and windows. Especially, we can see the planarian in the glass when looked carefully. When you observe in a slightly algae or bacterial cluster area, you can select even very small species. Usually, by drawing an “S” shape, they can move very slowly or with a visible speed.

Are Planaria Dangerous to Fish?

Considering the relationship between planarians and other living things in the ecosystem, it cannot be said that they are harmful. They consume all kinds of microorganisms that they can catch and swallow. With these features, they are nutrient partners in aquariums. There is no risk of contamination or harm to fish. On the contrary, we can say that it is good live food with its nutritious feature. Especially juvenile fish are a good food source. However, allowing these creatures, which emerged as a result of bad conditions, to survive means that water quality is compromised. They should not be allowed to reproduce within the same ecosystem.

Are Planaria Dangerous to Humans?

Aquarium planaria have no known harm to humans.

How to Get Rid of Aquarium Planaria?

  • Avoid overfeeding in the aquarium. The food left in the aquarium as a result of overfeeding triggers the planaria infestation. Especially protein-based feeds cause more planaria infestation.
  • It is the healthiest method known to detect deteriorations in water quality and take action immediately.
  • Placing planarian traps in the aquarium, making frequent bottom siphon and water changes.
  • Planaria infestation can be combated with medication, although it is not recommended.
    Planaria are known to decrease as the water temperature increases. Increasing the temperature to a height that the aquarium can handle will slow the invasion.
  • A piece of meat is placed in fabric and placed on the floor. A container or sachet can be placed underneath to prevent it from dispersing when taken out of the water. Plenaries that will be collected in this piece of meat at night will be removed from the aquarium.

In order to get rid of planaria, the negativities in water quality must be eliminated. Reproductive systems are simple but effective. They can reproduce sexually with the clumps of eggs they leave in the environment, even if they are dissected asexually. It is not possible to fight one by one physically. For this reason, it should be the primary method to clean the aquarium conditions to the extent that they cannot live. Frequent, detailed bottom siphon and water changes accelerate the recovery process. It is necessary to make sure that the filter system provides the biological cycle. In an aquarium with a high fish load or in an aquarium that does not have sufficient filtration, precautions must be taken to achieve this balance. No dead point should be left in the deep area, away from circulation as much as possible.

If you want to get rid of the existing ones as soon as possible; A piece of meat is placed in fabric and placed on the floor. A container or sachet can be placed underneath to prevent it from dispersing when taken out of the water. Plenaries that will be collected in this piece of meat at night will be removed from the aquarium.

Most species cannot survive at high temperatures. This is the reason why it is seen in aquariums, especially in winter, and rarely in summer. They are not seen at 30 degrees C and above. It is possible to get rid of planarian as a result of keeping the water temperature at this value for 3-4 days.

It can also be fought using chemicals. However, as it can be understood from the points I have explained, there is no need to incur such a risk and expense to get rid of these creatures.

Apart from these, planaria traps are sold in pet shops and they can be used to eliminate planaria.


Perhaps you will notice these creatures that you did not know before this article. Don’t let a few planarians seen in the aquarium make you worry. It would be best to consider the event calmly and act consciously by reviewing the stated issues.

There is no 100% safe and effective way to get rid of planaria. The healthiest way known to prevent planaria infestation is to improve water quality. Real success can be achieved by detecting and intervening in what is impairing water quality.

🐠𝙃𝙋 Team
🐠𝙃𝙋 Team
We're just like you - aquarium enthusiasts who love aquatic life! We've been caring for and breeding all sorts of freshwater and marine aquarium fishes, plants, and other pretty little creatures for years. We love sharing our knowledge with other fish hobbyists, and this article you have just finished reading is the best proof of that. You can read more about us here.

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