Unkown Disease

[manmeetdhatt]

One of my discus today had a long string of faeces hanging out of its bottom it was red,brown and whitish in the same strand of faeces.My small young discus had the same but only brown colured faeces and it took some time trying pass it. I change the water weekly and put in dechorinating meds only. I have some bristlenoses,angels, discuses,harquelins,black neon tetras and most of them,thier colour is gone dull. I really don't know what meds to give and am really confused and non of them seem to be growing

Manmeet

 

[Tokis-Phoenix]

What do you feed these fish and how much and often? Sounds like the fish could be constipated.