Discus heads down and hides in corner

[thongle]

So i have a 65gal tank with gravel floor and some rock. First i brought home 4 - 2 inch pigeon blood, they were shy at first but then got better. 2 weeks later i added 2 - 3 inch red melon, and 2 - 4 inch pigeon.
Now the small pigeons stay in the corner for most of time,i noticed that they are kind of shaky when swimming,and there are many pepper on their head and along the fin. The big pigeons often stand head down and not eating.
Temp is stable at 86. I have sufficient filter and air pump. There are also some guppies and platy in the tank. I dont know if it's a big deal to the discus. I'm new with discus so i know very little. Please let me know how to make them better. I'm so desperate right now. Thank you!!

http://i198.photobucket.com/albums/aa88/glasseslove/IMG_2385.jpg (http://s198.photobucket.com/user/glasseslove/media/IMG_2385.jpg.html)
http://i198.photobucket.com/albums/aa88/glasseslove/IMG_2384.jpg (http://s198.photobucket.com/user/glasseslove/media/IMG_2384.jpg.html)
http://i198.photobucket.com/albums/aa88/glasseslove/IMG_2383.jpg (http://s198.photobucket.com/user/glasseslove/media/IMG_2383.jpg.html)

[PP_GBR]

TL

Did you buy all your discus from the same source?

[JOSNNGUYEN]

Hey Thong. Have you check all your water parameter? Nice tank by the way

[Elliots]

Water parameters? Temperature? Is your tank cycled? How often and how much water do you change? If everything is good it just may be bullying with the smaller fish hiding. This is your first post. If you have not been reading this site I'd say you have tens or hundreds of hours of reading to do.

[Bill63SG]

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