Ammonia is a natural chemical byproduct of processes such as they breathe, eat and excrete.
While it is naturally occurring, excessive amounts of ammonia have the potential to have lasting and permanent health effects on your goldfish, and it is best if it is avoided.
When ammonia builds up to a toxic level, it “burns” the goldfish’s eyes, fins, gills, and skin.
When setting up a new tank, it is important to get a proper cycle (which can often take up to a month to achieve) going so that you do not cause “new tank syndrome”.
Because the water is not cycled correctly, ammonia accumulates faster to toxic levels.
Additionally, the water in the bag from the pet store may have accumulated excessive amounts of ammonia and should not be added to the existing cycle.
If your goldfish is in a tank or bowl without a filter, ammonia will undoubtedly be a problem without major and frequent water changes, which can be stressful to goldfish.
The smaller the enclosure, the more likely ammonia is to build up to a deadly level and damage your goldfish’s health.
When this happens, goldfish do not initially give off any physical signs other than being lethargic.
When goldfish begin to heal from ammonia burns, their scales turn black as a response to healing.