I have algae in my aquarium!

There are many causes for algae blooms, but they are a recurring problem that must be dealt with as soon as the first signs of water “contamination” appear.
Often considered a never-ending nuisance, algae can be divided into two types in aquariums: good and bad algae. Good algae are found in very small quantities and indicate good water quality. Their growth is regulated by algae-eating fish and they can easily be removed when cleaning the tank. Bad algae, on the other hand, are invasive species that are not very aesthetic and show that the water quality is not good. Now, it is still necessary to know how to recognize them in order to treat them accordingly.

The different types of algae

Blue-green algae

They are so called because of a pigment that gives them a bluish tint, even a little green and blackish. They can be recognized by their acetone smell and their slimy appearance on aquarium surfaces. Mainly due to a bad balance in the aquarium, this is why they are usually found in poorly maintained or newly launched tanks. It is important to check the water parameters, especially the nitrate and phosphate levels.

Green algae

There are about 1300 different species. They are found in the form of a point and have a fluffy appearance. There are 2 varieties of green algae: filamentous and encrusting.
The former prove that there is a good balance in the biotope. Similar to cotton fiber filaments, they can be easily removed by hand because they settle on artificial decorations and plants. If they are too important, they prevent the light from illuminating the plant and make it rot.
Green algae encrusting form a greenish-brown crust on the glass surfaces of the tanks and often come from excessive lighting.

Red algae

These are mainly marine algae even if some species have adapted to fresh water. We can differentiate a red algae from a green algae by dipping it in alcohol: if the red pigment remains intact, the green coloration disappears completely. This algae settles on plants with slow growth and often proliferates in an environment where carbon dioxide is lacking.

Brown algae

They appear in case of lack of light or are present as soon as the aquarium is put in water, but disappear by themselves in a few weeks. They can be recognized by their rapid spread on the tank’s decorations, resembling a fine rusty dust. As soon as you run your finger over it, it disappears.

How to eliminate them?

A new tank

The most important thing is to place the aquarium away from direct natural light or an excessive light source.

In this new habitat, it is advisable to install fast-growing plants, as plants and algae struggle to store as much phosphate and nitrate as possible, and often the algae win this nutrient battle. Also, change the water regularly by changing at least 10% of the volume every week. You can also add CO2 for the good growth of plants.

For the population, it is necessary to avoid at all costs the overcrowding of the individuals and not to have a too narrow tank: the fish produce a lot of nitrates and phosphates which will come to feed the algae. It is also important not to overfeed them. You can also use “algae-eating” fish that come and graze on the algae deposited at the bottom of the aquarium.

Chemical control

There are different chemical products available to fight against the appearance and proliferation of algae.
Some products are copper-based and are mainly intended for brush algae that appear in clumps.

An aquarium bactericide may also be sufficient: it maintains the tank and inhibits the growth of certain algae.

As a rule, chemical algae killers are not recommended, because although they can significantly reduce the number of algae, they also reduce the activity of the plants. If the plants are small or do not grow, the algae will take over.

Controlling algae with lighting

To fight against algae growth, it is also advisable to install good quality lighting and to adjust its duration, i.e. between 8 and 12 hours maximum per day. It must be adapted to the plants according to its power and the light spectrum it gives off.