Hello; Here is the rule of thumb that makes sense to me. When the last visible spot is gone keep up the salt treatment for at least ten days.( note this includes keeping temps over 85 degrees F)
This extra time will give any unhatched eggs time to hatch out and be killed. Also you might miss a few spots on gills or such.
A question that I do not recall seeing the answer about is if any other fish ever had ich spots. If they did not then that one fish may have had some other problem.
One other thing. If you have multiple tanks all equipment used in the infected tank should not be used in other tanks. At least for a time.
This extra time will give any unhatched eggs time to hatch out and be killed. Also you might miss a few spots on gills or such.
A question that I do not recall seeing the answer about is if any other fish ever had ich spots. If they did not then that one fish may have had some other problem.
One other thing. If you have multiple tanks all equipment used in the infected tank should not be used in other tanks. At least for a time.
