The frequency of cleaning a fish tank depends on factors such as the number and type of fish, tank size, filtration system, and whether the tank is planted. However, general guidelines are as follows:

• Partial water changes: Most aquariums benefit from changing about 10-30% of the water regularly. This is commonly done every one to two weeks. For example, changing 10-15% of the water every two weeks is typical for many tanks

, while some recommend 10% weekly to 25% every other week for established tanks

. Weekly partial water changes of 30-50% are also common, especially in tanks with higher fish density or less plant coverage

• Full cleaning: A more thorough cleaning of the tank, including vacuuming the gravel, wiping down the glass, and cleaning filter media, is generally recommended about once a month

. This helps remove debris, uneaten food, and algae buildup.

• Filter maintenance: Filters should be checked regularly and rinsed in aquarium water (not tap water) to preserve beneficial bacteria. Filter media may need cleaning monthly or as flow rates slow

• Adjust based on tank conditions: If the tank develops excessive algae, smells bad, or water quality tests show elevated nitrates or ammonia, cleaning and water changes should be done more frequently

. Planted tanks with good filtration may require less frequent water changes, while tanks with messy fish like goldfish may need more frequent maintenance

In summary, a good routine is to perform partial water changes weekly or biweekly (about 10-30%), clean the gravel and glass as needed, and do a full cleaning including filter maintenance about once a month. Testing water quality regularly helps tailor the cleaning schedule to your tank’s needs.