Originally Posted by
Rapture
Have you tested your water for ph swing and microbubbles? It looks like you have quite a bit of bubbles on the inside of your glass. If you change water daily, which would be a very idea after adding 8 discus to your tank, the bubbles may very well stress the fish and make them sick. If your source water has a ph swing, that can also be quite stressful to the fish. The remedy to this is to age your water. My other advice is to feed the fish a good diet, only what they will eat over a few minutes, especially while your biofilter is catching up with all the fish being added at once.