Hypoxia
Fish can suffer from a lack of oxygen in the water, and if left uncorrected, they will eventually become weak and vulnerable to viruses, bacteria, fungi, and parasites.
They will not be able to resist diseases and will die from any of them. Not to mention that they can simply suffocate if the oxygen content becomes too low.
Among the main reasons are usually weak aeration, relocation of the aquarium and a large amount of organic waste. The latter seems not obvious, but for example, excrement, uneaten food residues, leaf fragments, in the process of decomposition, actively interact with oxygen dissolved in water, significantly reducing its concentration.
Symptoms:
Fish spend most of their time at the surface of the water, where the concentration of dissolved oxygen is higher. Sometimes they try to swallow air bubbles.
Treatment
The treatment is very simple. The first step is to increase aeration, if necessary, add additional spray stones. Tidy up the aquarium by removing organic waste. In the case of relocation, when for every 2 liters of water there is one medium-sized fish (4-5 cm in size), it is advisable to purchase a tank that is more spacious.
