Dirty water can be detrimental to the health of fish kept in aquariums. It is crucial to maintain good water quality to ensure the well-being of your finned pets. Dirty water can contain high levels of ammonia, nitrites, and nitrates that can cause stress, disease, and even death in fish. Regular water changes and proper filtration are necessary to remove excess nutrients and toxic compounds from the aquarium water. A general guideline is to replace 10-15% of the water every week. Make sure to treat the tap water with a de-chlorinator before adding it to the aquarium. Also, choose a filter that is appropriate for the size of your aquarium and the fish you keep. Additionally, use an aquarium water test kit to monitor the pH, ammonia, nitrites, and nitrates levels in the aquarium water regularly. High levels of these compounds can cause health issues for fish.