Hypo salinity is a method of treating marine fish parasites by manipulating the salinity of the water and maintaining marine teleost fish in a hyposaline environment. The salinity range for this treatment is generally 12-16ppt. This method gives aquarists an option to using copper-based medications or harsh chemicals to treat this common parasitic infection.
When it comes to saltwater aquariums, hypo salinity means bringing the salt content down to a range of 1.010 to 1.013 SG to be effective for parasite control 31. When reducing the salinity, be sure the pH and temperature of the water do not differ from the current water conditions for the fish.
Ideally, fish with Cryptocaryon are quarantined in a hospital tank, where they can be treated with a copper salt or using hypo salinity, 1.009 specific gravity. The display tank needs to be kept clear of fish for 6–9 weeks, the longer the better.