Feeding minnows...

[rallysman]

really, your oscar does NOT need feeders.
The pbass may be converted if they are still young. Have you tried to starve them a little bit at all?

 

[guppy]

I have often used shiners and cutlips from bait shops with no problems, it is safer to go through the salt and quarantine routine first. I have also used wild caugt chub, sunnies, killies, and gambusia. I try to keep them for 2 weeks in water containing 2 teaspoons salt per gallon before using them. I have occasionally had to dose them with Paraguard as well.
Filthy Sanchez, it sounds like the pacus left enough shredded fish in the water to cause a bacterial bloom.

 

[Filthy Sanchez]

Treating your feeders before is a quality move, has anyone thought about mosquito fish? They are cheap to get a hold of and I think if you treat them first they'd be a good option.

 

[BigPleco]

First off, I would keep those minnows in a different tank for a while. then if they seem ok, go for it and feed them. Otherwise you may have some big time trouble with diseases.