Even if your angelfish does not grow to be very big, it’s always better to have more space than necessary.

If you need to raise your pH level, this can be done in several ways. Add crushed coral, which can raise the pH level. You can also add baking soda, shells, and chemical buffers sold at pet stores. [2] X Research source If you need to lower pH levels, adding wood to the tank can help. You can also buy a chemical buffer made to lower pH.

Rocks and hiding places are important for angelfish. Stop by your local pet store and pick out a variety of tank decorations. Try to add things like floating drift wood, as this reflects an angelfish’s natural environment. Also, plants that stand vertically are great for an angelfish tank.

You should keep a thermometer in the tank. If the water gets too hot or too cold, adjust your heater accordingly.

Younger angelfish will need more live foods than older ones. As you angelfish age, you can feed them more pellets and flakes than live foods. For general guidelines, younger angelfish need to eat 3 to 4 times a day. After they grow to full size, however, cut back the amount of food and stick to a strict schedule. Angelfish will overeat and become overweight if fed too much. [5] X Research source

Use one to two cups of the existing tank water to clean the filter’s sponge. Remove the water from the tank. Then, unplug the filter and remove it from the tank. [7] X Research source Wash any gunk or grime from the filter. You should wear gloves, as the filter will be slimy. Then, use any leftover water in your bowl to give the filters and tubes from the filter a good scrub. You can then reassemble the filter and place it back in the tank.

You may have to adjust temperature and pH levels after changing the water.

Excessive slime and clamped fins can be a sign of a very serious disease called angelfish virus. If you suspect your fish has the virus, it may need to be put to sleep as there is no cure. White chalky feces, a lack of appetite, and weight loss can also indicate disease. There is also a common disease called ich that causes white spotting due to parasites. It can be treated easily with medication, so keep ich medication on hand when you have angelfish. [10] X Research source