Angelfish prefer soft water with a slightly acidic to neutral pH. They have relatively high requirements for water quality. Suitable water quality conditions include a pH value between 6.5 and 7.5 and a hardness between 1 and 10 dh. Moreover, angelfish also have certain requirements for water temperature. The suitable water temperature range is 22 - 28°C. Within this temperature range, angelfish have a strong appetite, grow rapidly, and are not affected by external temperature changes.
To keep the water quality clean for angelfish, it is recommended to regularly change the water with fresh water. Replace about one-third of the water volume every week. Also, set up a filter to keep the water flowing and increase the dissolved oxygen content. In addition, angelfish don't like direct sunlight. Therefore, the aquarium should be kept away from places with intense sunlight. When raising angelfish indoors, six hours of light exposure per day is sufficient.