API Ammo Lock 237mlAmmo-Lock is a liquid treatment proven to protect fish cells from ammonia. If the aquarium tests positive for ammonia, act quickly by doing a partial water change and then neutralize the ammonia. Ammonia is toxic to fish cells, especially the gills. Works instantly, in both fresh and saltwater aquariums, to detoxify ammonia and remove chlorine and chloramines. Ammo-Lock locks up ammonia in a non-toxic form until it can be broken down by the tank's natural biological filter. Eliminates fish stress and promotes healthy gill function.