Okay, I'm almost positive that Pi has fin rot on the edges of her fins.
Here's a pic:
I'm not so sure about Peach though, when I first made this thread, I thought these bits of fin might be it(BTW, sorry for the poor quality of this photo):

But now I'm not so sure. I have not witnessed any fin dissolving/falling off, and these places on the fin are looking pretty natural to me. when light is shone on the grayish parts, it looks more blue:

What do you think?
also, some more treatment advice is helpful for Pi.
(i.e, how much water to dissolve salt in)
Thank you, and sorry for replying so late, ~Saphira