discus plague?

Hi,

We made a bad decision and introduced some new discus and angelfish into our tank without quarantining them. These were fish we had gotten from a farm so they had already been thru the stress of being transported cross-country. All the new discus and all but one of the angelfish died within a few days. Now our old wild discus that we've had for 6 months have turned dark and their eyes are cloudy. Our old angelfish are not as active as they used to be and we've lost a few other fish as well in our community tank. Any suggestions on how to treat them? We tested the water and everything checked out perfect, so we're wondering if they've contracted some disease from the new fish? I read about the discus plague and even tho it says it's supposed to be rare, I'm wondering if that's what they have. Also, it's only been a week since we introduced the new (now deceased) fish...can it hit that quickly? Thanks for any help you can offer.

it's a 60 gallon tank and we do a 10 gallon water change about every 3-5 days. everyone was doing great until this last week. we tested the water as soon as we saw everyone getting sick but all the factors came out perfect. the ph is 7, no ammonia, no nitrites and the nitrates were less than 25. we did a water change then to bring those down. we also have german blue rams, neons, danios, rummies, brilliant rasboras, plecos, a black ghost knife fish, and catfish. all the other fish, except the rams, are doing ok. we had a balloon ram before we introduced the new fish, then we added 5 new german rams. we've lost one, and have another that is not looking too good, but that might be loss from shipping. any ideas? thanks

thanks for your response how warm do they like it? we have it at 80 now.

sorry one more question...will this temp be ok for my other fish? thanks

we have 3 large ones, as well as neons, german rams, rummies, angelfish, danios, brilliant rasboras, plecos, a black ghost knife fish and catfish. The largest discus is about 6-7 inches, the other 2 are 4-5 inches. I don't know how old they are...we got them at a trade show. they're wild discus.