My discus got sick and I do not know what to do?!?!?

[littlej2455]

I have had my discus in a community tank for about a year now. Everything has been good, and I have not changed anything since I have had the discus. All of the water qualities are good. Just a few days ago, I noticed that some of the fins of the discus are not the regular shape. The dorsal fin looks like it is cut from the tip to its body, kind of like it was separated. One of the discus's eyes is also puffy with a white spot on his pupil. Can you please tell me what's is the matter with my fish? How did this happen? How do I fix it. Thanks!

[ILLUSN]

check your water chemistry, sounds like ammonia or ph shock please check ph temp ammonia nitrate, nitrite get back to us.

give a good water change after you've done your checks and add salt at 1tsp/40L