It is important to keep any aquarium clean, but it is even more important if you keep fish in a small bowl, since these containers usually do not have filters and the small water volume means that contamination is more concentrated. It is especially important to clean small bowls weekly because failing to do so can quickly result in disease and death to fish.
Materials You Will Need
Clean 2-cup container
Water conditioner product
Small fish net
Prepare the New Water
Unlike large tanks, where a portion of the water can be replaced with each cleaning, cleaning a small bowl usually means replacing the entire water supply. To avoid major shock to your fish, it's critical that the water be treated to remove harmful substances, and aged to equalize the temperature and pH.
Regardless of what your water source is, it should be treated to eliminate chlorine, chloramines, heavy metals, and other potentially harmful substances. Maintaining a consistent water temperature is also important to avoid stressing the fish with an abrupt temperature change. Lastly, tap water contains dissolved gases that dissipate after a short time, often changing the pH of the water, which is another stress factor for your fish. All of those issues can be addressed by treating your water and aging it overnight before adding it to the fishbowl. The process for aging water is a simple one:
Fill a clean bucket with water from the tap. You may want to buy a bucket to be used only for fish water, to ensure that it never contains any soap residue.
Add a water conditioner product. Choose a product that is advertised to instantly remove chlorine, neutralize chloramines, and detoxify heavy metals.
Let the water sit until the next day before using it. If you have small children or a pet such as a dog, put the bucket in a closet to ensure it's not disturbed.
After the new water has aged overnight, you can proceed to cleaning the fishbowl.