i have a small 1" gt that is beat up badly but still eats and swims. i put him in a tank alone. i heard salt will help heal him but how much do i add per gallon hes in a 40 galon and should i pre mix it?
I would just do water changes and keep the nitrates below 20ppm. You could also do a methylene blue bath for 30 minutes. About 1ml per gallon for 30 minutes.
I will also add to that info that there are bacterial diseases such as Flexibacter columnaris (Flavobacterium columnare) that have also been effectively treated with salt. (sodium chloride) This is well documented within the aquatic industry with studies and their results available online. There is no debate on that subject.
When used at appropriate levels, sodium chloride can do much more than simply help with certain parasites.
While I enjoy some of the articles written by the skeptical aquarist, I have always taken some of his info with a grain of 'salt'.