With the Tetra TestStrips Ammonia you can test the ammonia content in your aquarium water within seconds. In aquarium water, ammonium is produced by the bacterial decomposition of uneaten food and plant matter as well as fish waste. Although ammonium is an important nutrient for plants, this is dependent on the pH level. If the pH level is >7, it can convert to ammonia (NH3) which is then toxic for the fish. Above pH 7 even in small amounts of 0.25 mg/l, ammonia will still pose a threat to the fish with symptoms like rapid gill movements, nervous swimming and loss of appetite. In higher concentrations from 1.0 mg/l and above, it can be lethal. Tetra TestStrips Ammonia with 25 single test strips for freshwater aquaria.