Yeah, with my nitrIte problem, One angel died, one acted really stressed (and still does, once in a while, for a few minutes) The male pearl had NO color... the female pearl was just like, "la de da... what's up, guys?" whistlin' everything's great... no signs of stress at all. Even the BN's acted stressed once in a while, but the female pearl was just doing her thing... it's wierd how that works sometimes...
Anyway, they are all fine now, except the one angel still scares me once in a while... she'll swim on her side for a second, or have her nose out of the water gasping for a second, and then just go back to swimming around normally. I'm afraid I might still lose her as a result of this, but at this point, there is nothing I can do except keep it stable... Same for you, just keep everything as stable as possible, (including keeping waterchanges the same as they have been) and hopefully nothing else dies.