Day 6 of protozin completed yesterday morning. Had a good look at all of my fish and they seem fine with the exception of one platy. She has a tiny white dot on her side which started out bigger at the beginning of last week. It has gradually got smaller but I can still see it although it is tiny now. Should just start changing water as normal or another dose of protozin? Also, does this mean the protozin is the correct treatment as the problem seems to have stopped as the one white fleck on the platy is minuscule?