Ammonia should be 0.
"Ammonia occurs in two states depending on the pH of the water. The unionized state,
NH3, is more toxic than the ionized state,
NH3+4,. The unionized state can invade the body tissue of marine animals much easier. Almost all free ammonia in sea water with a normal pH is in the ionized state, thus less toxic. As pH rises, the less toxic ionized state decreases and the more toxic unionized state increases. For example, a toxic level of ammonia as
NH3 may be present with a pH of 8.4 being lethal , but the same level of ammonia as
NH3+4 with a pH of 7.8 may be tolerated. Higher tank temperatures can also effect the toxicity of ammonia..
Testing for ammonia is extremely important. Ammonia will be elevated during a new tank cycle, but can also be elevated in established aquariums if the aquarium maintenance is not maintained. If water is not changed regularly, filters are not kept clean, if the tank is overstocked, or if medication is used that disrupts the biological cycle ammonia levels can increase. Test immediately anytime you have sick fish, or a fish death. Ammonia is measured at parts per million (
ppm). Aquarium water quality is critical to the health of tank inhabitants. Lethal levels of ammonia can accumulate very rapidly in the absence of true nitrifying bacteria. The ideal ammonia reading should register at "0"
If ammonia is present, fish may exhibit the following symptoms:
Rapid gill movement
Clamped fins
Bacterial infections
Mortality
"