Vet Q & AHow to save my sick freshwater fish after an ammonia spike?
Monitor water chemistry using a home test kit or submit a water sample for testing. The local Petco may do this for free or for a small fee. Aim for an absence (0 ppm) of ammonia and nitrites with nitrates at 20ppm or less. Perform partial water changes to stabilize chemistry and/or to improve water quality. Use only conditioned water that is temperature matched to prevent stress or shock. Pristine water quality is the foundation for healing and recovery from infection or injury in fish. You can use plain aquarium salt (NOT table or Epsom salt) as a general tonic to reduce stress, improve gill function and aid in recovery. Dissolve 1 teaspoon of salt per gallon of water in a cup or two of water and gently pour it into the tank. Treat for 14 days then reassess the condition. An "all in one" product, such as Lifeguard (by Tetra), can be used concurrently to treat infection or parasites. Find one in the aquarium section of the local Petco. Follow label directions carefully and remove the carbon filter insert during treatment if indicated.
Updated on September 24th, 2025