where did I go wrong

[mizzoumed02]

I bought several discus a little over a year ago from a breeder, not a big name one thoug, some of them went into a planted tank and the rest went into a BB tank. Both tanks got daily water changes around 50% and then the tanks were refilled with a 50/50 mix of rodi and tap water that was aged and headed to the tank temp. I had AC 500 on the tanks and then hydro spounges. The filters had prefilters on them also. The discus got fed a combintaion of BH, BW,BS. The discus in the planted tank did just fine and then the ones in the BB slowly died off one by one. I'm not sure what happened. The water always tested out fine.. The feeding routine didn't change between the tanks either. I know I didn't buy from a Known breeder, but I don't know what happend. Does anyone have any ideas??

[RyanH]

What were their symptoms before they died?

[mizzoumed02]

the fish would just stop eating and turn dark. Almost like they had Flang or some type of internal Parasite, but all the other fish would be just fine, eating good and no white feces noted. The whole proccess took place over approximatily 8 months before they all died. Like I said though, the two that were in the planted are doing just fine and are around 5" at this point