Discus fighting problem

[Cookie_discus]

I recently added three 3.25'' discus in my 55g tank over the week. One is blue diamond, one is red turquoise and the other one is blue turquoise. The blue diamond is picking at the other two during the feeding time and the blue turquoise always chasing the red one all the time. What can I do to solve this problem? I have 6 cardinals, 11 sterbai cory and two big driftwoods and one small driftwood in the tank aslo. The temp is 82-82.7

[Kyla]

when i brought home my first discus from kijiji, i made a lot of mistakes, including only getting a few discus. they are aggressive, schooling fish. this means they feel more secure in a larger group, and having more individuals spreads out their aggression so that (ideally) no single fish gets picked on all the time. can u tell the group a bit more about your tank? water parameters, filtration, water change schedule and %, do u age ur water, is there substrate in the tank, can u provide pics etc?

edit: do u already have some discus in the tank?

[adrian's fish]

you have to add more discus , they do well in groups of at least 6 discus. Try to buy them from the same source and quarantine them before you add them to your main tank. Good luck

[Cookie_discus]

106136106137I have 25 lbs nature gravel for the substrate, I do 20% water change twise a day or once in a three days and age the new water for 24 hours, PH 7.8, Kh 5-6, one ac 110 with Seachem Matrix, floss and purigen for filtration but I am going to add a ac 70 this weekend with bio rings and floss. As you can see in the pic the red one is hiding at the upper left corner in the tank.

[Cookie_discus]

Ya they all from the same lfs and I going to buy two more at the same place too.

[Cookie_discus]

Forgot to mention that I use almond leaves to light tinted the water as I like it a bit yellow and it looks nature. I also use a aquaticlife RO unit for the water but I collect the water before the membrane so the water only got filter from the sediment and carbon stages. The PH and KH are same with the tap and I still need to age the water for 24 hours as the PH will rise up.