Except for fish, snails, plants and other animals in the aquarium and home to plankton, causing algal blooms – filamentous and unicellular green algae. In conditions of medium or low light, low water temperature, phytoplankton multiplies slowly, the water remains transparent. Intense increase in the mass of microorganisms contribute to some factors.
The main reason for the enhanced growth of microalgae – a large amount of light. If the aquarium lighting is too intense, water can go green even in winter. During the summer, "blossom" is enough natural daylight, especially if the aquarium is exposed to direct sunlight.
The second important factor is "blooming" of water, raising its temperature. Active division of the phytoplankton begins when the water temperature becomes above average.
The presence in water of excessive amounts of organic matter is another factor contributing to the proliferation of microorganisms. If you badly need the hygiene of the aquarium and regularly overfeed the fish, in this medium began to share in the phytoplankton, especially of a Euglena green.
The last factor affecting the purity of the aquarium – the lack of inflow of clean water. If you skimp on the filter and aeration, suffers from chemical and biological balance of water that leads to the transformation of the aquarium in "the swamp".
The most radical way of getting rid of "bloom" - a complete replacement of water with the subsequent shading of the aquarium. If you completely change the water problem, it can change to third and cover the aquarium from light. Without lighting the phytoplankton will cease to reproduce, and ciliates, for which he is feed, clean water. In addition, the aquarium can settle Daphnia, shrimp, catfish, snails, which also feed on microscopic algae.
If the water turned green – reduce the amount of feed to the tank inhabitants. Normal fish have to eat all in 5-15 minutes. For a day or two you can even completely stop feeding the fish enough and the food which is already in the water. Watch out also for the correct operation of the devices for filtering and aerating aquarium – this helps to avoid excessive accumulation of organic matter in the water.
A slight greening of water for fish is not considered dangerous, but if the bloom is strong enough – it could be fatal for some of the inhabitants of the aquarium. Green algae clog gills of fish, and besides, in the dark phytoplankton needs oxygen, resulting in the "official" aquarium inhabitants start to suffocate.
If all your efforts do not lead to purification of water, try to use chemicals – you can buy them in pet stores. In compliance with the instructions and the specified doses of these substances are safe for aquarium inhabitants and plants.