How to make aquarium fish happy?

Fish are often injured because they fight with each other while forming a hierarchy. It is still possible to occur bacterial infections or parasites, however, it is difficult to detect them. Still, it is necessary to do this at the initial stage, to put the infected fish in quarantine and treat to avoid the spread of the disease.

If the fish rubs against the aquarium, it is most often trying to shake off parasites and therefore requires treatment.