- Water Quality: This is one of the most common causes of death for goldfish. Poor water quality can be caused by a build-up of waste, such as food or feces, in the water. It can also be caused by a lack of oxygen in the water, which can be caused by overcrowding or a lack of filtration.
- Temperature: Goldfish are cold-water fish, and they cannot tolerate extreme temperatures. Temperatures above 85°F can be fatal for goldfish.
- pH: Goldfish prefer a pH level between 6.5 and 7.5. A pH level that is too high or too low can be fatal for goldfish.
- Ammonia and Nitrite: These are two chemicals that can build up in a fish tank if the water is not properly filtered. Ammonia and nitrite can be toxic to goldfish.
- Chlorine and Chloramine: These are two chemicals that are commonly added to municipal water supplies. Chlorine and chloramine can be harmful to goldfish if the water is not properly dechlorinated.
- Disease: Goldfish are susceptible to a variety of diseases, some of which can be fatal. Common goldfish diseases include ich, fin rot, and swim bladder disease.
- Accidents: Goldfish can also be killed by accidents, such as being dropped or being sucked into a filter intake.