Okay, since it is a new tank, do not use the clarifier. It is foggy because it has an ammonia spike and a bacterial bloom from either adding fish too fast or feeding too much. It should currently have only one fish of no more than 1-2 inches in length in it and be fed once a day, only 1-2 flakes of food. So adding a chemical could make things worse. Instead, change out 1-2 gallons of water. When you add the new water, use AquaSafe Plus and SafeStart Plus. The SafeStart Plus should help clear the water over a few days, and help prevent toxic levels of ammonia and nitrite. You will still see stress levels, but that's okay.
For future reference, you leave the fish in the tank, keep all filters and aeration operating, but take the carbon out of the filter for about 3-4 hours, then put it back.
Date published: 2018-06-14