Our commercial grade of Formaldehyde or Formalin solution contains 15% methanol as a stabilizer. It is a colorless liquid with a strong pungent odor and is soluble in water and alcohol. Its multiple uses include as preservatives, embalming fluids and as a corrosion inhibitor. Store above 40°F Freezing temperatures can cause formaldehyde to form paraformaldehyde. This appears as white inclusions. Do not use if using formaldehyde to treat fish parasites. Paraformaldehyde is toxic to fish. Store above 40°F (4.4°C).