Iodine free common salt (Sodium Chloride) must be one of the most useful remedies for the aquarist. Many freshwater fish such as the live-bearers, appreciate some salt in the water as a matter of course but salt is often used as a general tonic and occasionally a "cure all" treatment for sick fish.

It is not fully understood how salt benefits fish and helps to cure disease, but it is thought that Sodium Chloride reduces the immediate effects of Nitrite on fish.

The table below illustrates the the uses of salt in varying solutions: