Algae in Planted Aquarium

Kinds of algae

Kinds of Algae
Kinds of algae

Many forms of algae grow in the aquarium environment and an algal bloom can quickly take over plants. It will compete with plants for light and nutrients until they will defeat them.

This is very hard to get rid of the them completely, they may slow down plants growth and as well look unpleasant and release toxins into the water. It may cause that plants are fish will be unhealthy. Algae will grow in any conditions, however it is possible to keep their level on minimum and prevents its spreading. Some kind of them may grow on a driftwood or rocks may even look very interesting and pleasant. It is beneficial for your display. It may also provide food for some kind of fish like otto or pleco.

Well-maintained planted aquarium will face less problems with algae than an aquarium with no plants in it. Algal blooms may showed up in the aquarium mainly when certain conditions will be ideal for algal growth. Luckily, you can prevent those conditions from developing.

Many types of algae may be present in the aquarium environment, but most of them are divided to a few groups. Main indicators of conditions good for algae are: iron(key factor), phosphates, as well as, ammonia, nitrites, too high nitrates(over 40ppm when plants growth is slow, when faster might be higher). Some algae will spread very fast, but some will develop very slow in the aquarium, like brush algae.

Single-celled algae

These kind of algae develop as single cells that won’t create bigger connections. Those algae may quickly spread and create an effect called ‘green water’. When it will appear in you set-up it is good to lower the light or even don’t use it completely for a few days and first make 50 % of water change and then every day for a few days make 20-30 % of water change. Before that it is good to wipe all walls and objects like stones, heater, filters elements, as well as squeeze mechanical filter media in the water from aquarium(water which you took from aquarium to the bucket). Single-celled algae blooms may appear in the new aquarium usually because of too bright light or too long light period, a combination of bright, direct sunlight and too much fertilizers or not enough weekly water changes while fertilizing.

Advice: Cleaning the aquarium glass every week, even when it appears like nothing is in there, it will help to prevent the creation of other algae. You can use cotton balls or special filter wool, which works very good as a mechanical filter media and it polishes a water.

Another interesting method of fighting with algae is UV light unit for aquariums, but they are not recommended for planted aquariums because the UV light will kill some useful nutrients. You may reduce organic substances but feeding you fish less or gravel high layer of your substrate. There are several algae treatments available specifically for ‘green water’ algae. . Most of them work by connecting the individual algal cells together into larger structures, which may be sucked up by a mechanical filter or siphoned away from the substrate during the maintenance.


Filamentous Algae
Filamentous algae

Filamentous algae

  Most common in aquarium, visible in many different forms – thread algae, hair algae, or blanket weed. When there are deficiency of nutrients, light is too bright and plants growth is too slow, those kind of algae may appear. It looks like hair threads which grows from plants to the top of aquarium. It is hard to get rid of it and you may treat some plants with peroxide or 1:5, bleach solution and cut off infected leaves or plants. Some plants are very hard to treat like mint charlie, or red ludwiga. Filamentous algae likes faster water movement. You can find a treatments in the store, but it is always better to get back good conditions in the aquarium instead and suite fertilizers more adequately as well as setting up co2 correctly. Seachem excel may help too.

Blue-green algae

The reasons of this algae is not clear. It appears with high nutrients level and bad water quality. Mainly not making enough water changes and lack of consistency. It looks like a thin, blue-green blanket on the substrate decorations and plants. It is slimy to the touch and breaks up easy. Your water also smells bad when you have it, because of toxins. Fish like pleco or otto won’t touch it. It can be sucked away but may show up again very quick.

Brown algae

The most popular in planted aquariums. It is not that scary like other algae but it may cause some problems. You may swipe it from glass and decorations make a water changes and try to reduce silicates in the water. It is common in new aquariums set up as well as after adding some kind of substrates rich in silicates. I would recommend to wash every substrate even if it’s Eco-complete.

Brush algae

Growth is very slow but it is mostly cause by co2 fluctuation or not adding seachem excel. If you won’t start acting it will start spreading faster and will cover leaves edges and many objects. It likes fast water flow, and looks like fur which grows up to 0.4 in.

Brush Algae
Brush algae

The reasons why those algae appears are unknown and therefore it is likely that there are no special conditions beyond those of a normal aquarium that encourage it to grow. You should remove those algae, manually, cut off infected leaves and clean it from driftwood or decorations. You can even pick them up pinching them. It is documented that Siamese flying fox (Crossocheilus siamensis) may eat this kind of algae. However, I reduced it’s level by cutting off fertilizers and stabilizing co2.

Using algae treatments

This kind of stuff should be used in the worst cases and when there is many kids of algae. Try to avoid this kind of solutions and use it when you really must and only temporary. Algae treatments with copper will affect plants in your aquarium first before algae. It may be toxic as well for plants and fish.

Natural prevention

The best way to prevent algae in a planted set-up. Strong plants growth, good balance in the water and proper fertilizing is a key. As well as proper light intensity and lighting period. Good filtration and water flow also helps a lot. Prevent aquarium from direct sunlight and add some clean up crew like amano shrimps, ottos, plecos etc. Plants produce allelochemicals which may also have big influence in restricting algal growth. Healthy, well-planted aquarium shouldn’t encounter bad algal blooms when everything else is proper.