Revive 1/2 Liter, Fish Vet. Treats 2.5 gallons per 1/2 once in freshwater systems. Treats 5 gallons per 1/2 once in saltwater systems. Revive is a complex product which has been formulated to treat the following list of common diseases, in both salt and freshwater aquaria. Oodinium in both saltwater and freshwater forms, aka Velvet or Rust disease. Also many forms of gill flukes, and gram negative bacteria. These latter are very often instrumental in causing the signs of hemorrhaging on the sides of fish. Revive eliminates the free-swimming stage of Oodinium, as well as Gill flukes and many gram negative bacteria. Revive is used in fresh and salt aquaria, with no harmful side effects. Revive does not harm fish, invertebrates, or nitrifying bacteria, and no test kit is necessary during treatment.