There are many common aquarium problems and they should be studied and understood when you get into the hobby so that you can both avoid and solve these issues when they arise.
Cloudy water in the aquarium, various algae issues, diatom or “brown” algae outbreaks, “red-slime algae” or cyanobacteria problems, fish disease such as “ich”, and dreaded tank crashes are all common aquarium problems.
While you will undoubtedly experience one or more of these issues at some point as an aquarist, if you are prepared and take all the necessary precautions they can mostly be avoided and when a problem does arise you will be able to quickly deal with the situation and prevent it from escalating and creating further problems in the aquarium.
If you are unprepared or take the incorrect steps to address these problems it can result in a long drawn out situation that will actually create further problems in the tank. Visit the web links below for more information on these common aquarium problems.