What is green algae

What types of green algae are there?

Before you declare war on the green algae in your aquarium, it is worth taking a look at the different types of green algae. Of course, not all 8000 species of green algae can be presented at this point, but since most of them rarely or not at all in the aquarium, this is fortunately not necessary. However, the following six types of algae, which all belong to the green algae family and which often occur in very different forms in aquariums, are of greater importance for the domestic underwater world:

Thread algae are - as the name suggests - relatively easy to recognize by their 5 to 20 cm long green threads. They colonize furnishings, plants, soil, filters and hoses. They can be removed mechanically with a wooden stick or a clean bottle brush, but if you want to get rid of the green threads permanently, you have to bring the water values ​​of your aquarium back into balance. The most common cause of thread algae is an oversupply of nutrients (CO², nitrate and phosphate). But a lack of nutrients can also lead to increased algae growth.

Read more about combating thread algae.

If the water in the aquarium suddenly turns green, it is called an algal bloom. The cause of this is often the green floating algae (Chlorophyta). The cloudiness is caused by the many spores of the floating algae, which (just like the thread algae) usually develop as a result of an excess of nutrients. Incorrect exposure due to too much sunlight or incorrect fertilization can be reasons for the fluctuating nutrient balance. In contrast to other types of algae, the algae bloom can be combated with the help of a UV-C clarifier, which uses UV-C rays to kill the algae that swim freely in the water. Other plants are usually not damaged in the process. However, the water should then be almost completely changed and the filter cleaned. With a little more patience, however, you will also be able to master the floating algae by adapting the nutrients in your aquarium to the needs of your plants. You can find out what measures you have to take here in the section "What countermeasures are there?"