The water change frequency for angelfish doesn't need to be daily. Depending on the growth stage and specific conditions of the angelfish, the water change frequency varies:
Juvenile and Sub - adult Angelfish: They require a daily water change. Each time, replace 15% - 20% of the water in the fish tank. After each feeding, promptly clean up the food residues in the water to prevent water pollution.
Adult Angelfish: You can change the water once every 2 - 3 days. When the temperature is relatively low, the water change frequency can be appropriately extended to once a week.
Discus Fish: It is generally recommended to change the water once a week, with each water change being about one - fifth of the total water volume. In summer, since the water quality deteriorates easily, it is advisable to change the water every 3 - 5 days. In spring and autumn, the frequency of changing water once a week can be maintained. In winter, the water can be changed about once every half a month.
Precautions for Water Change
Water Quality Testing: Before changing the water, use water quality testing tools to check various indicators in the water, such as the pH value and ammonia - nitrogen content, to ensure that the new water quality meets the survival requirements of angelfish.
Water Temperature Control: The temperature difference between the new water and the old water should be kept within 2℃ to avoid affecting the fish due to sudden water temperature changes.
Gradual Water Change: Avoid changing all the water at once. Instead, retain some of the old water and add an appropriate amount of new water to maintain water quality stability.
Choose the Right Water Source: If tap water is used, it needs to be left standing for more than 24 hours in advance to remove chlorine and other potential harmful substances.