Welcome to AC! You might get a better response in the angel/discus cichlid forum.
Both fish look to me to have frayed fins...what are your water parameters; ammonia, nitrite & nitrate? How often do you change water & how much each time? What foods do you feed & how often? What size tank? Any other fish? How long have you had them?
We need a lot of info, help us to help your fish. They look to need some help, what size are they? Tell us everything...& then we'll ask some more.
When any problems arise in my tanks my first answer is to change water, a lot & often.
Thanks a lot for your response and my answers are below.
Daily I am changing water around 50%. Currently i am giving tubifex and blood worms 3 times a day. Tank size is 10 Gallon as I can't afford big size. I have purchased them on 10th of this month. Size i don't know may be 2-3 inches.
I don't have a kit to check water parameters like ammonia, nitrite & nitrate but for coming down the PH I have put Almond leaves and changing water regularly so that ammonia can't raise up.
No! Not in a 20g either. I say the minimum is a 4ft 75g for the short term. Discus get to be big fish, 6 inches in diameter...& they prefer to be kept in groups of at least 6...(or mated true M & F compatible pair in a minimum of a 29g) (30 inches x 12 x 20 high)...but only if you have another tank to raise any fry in.
Discus are a lot of work!! Daily water changes & several feedings per day was what I tried to give them...but I'm not sure I want to try them any time soon again