How do you clean a fish tank?

For a small tank, pour the water and fish into a clean basin first, rinse the tank directly, then return the fish and water and add pre-prepared aged water. For a larger tank, use a magnetic scraper to remove moss and grime from the glass, then clean the filter carefully, mainly the surface physical filter layer; do not over-clean the rest to preserve the nitrifying bacteria’s biological filtration. Never use any chemical detergent when cleaning, as it can harm the fish and aquatic plants.