I need some help, think tank may be diseased

[we4wieners]

I have a 75g with blood parrots, geo's, CK, and bichirs. my parrots have what seem to be scraggly gills with like tiny red things in his gills. the smaller parrots gill is a little scraggley also.
checked my water: ph-6.4 ,Nit-0 ,Amm-0. temp is 80'
I have no idea what it is. Just noticed it....help!

 

[we4wieners]

It's also starting to get stress marks along the fins...I'm really getting worried because the marks weren't there yesterday. here is a pic

 

[Lupin]

What test kit are you using?

 

[we4wieners]

API.......