I do not want to treat the whole tank but I think its the safe thing to do as if the eggs are in the sand there is a chance they will find some one else. I have a naso, clown tang, powder blue, sail fin , aussie tusk , hippo. I am done with any more loss when I can treat the fish. I also have a problem with my qt set up. Moving on I will prazipro all fish along with hypo