Stunted Discus

[Dappled]

Hello!
I am both new to this forum and new to keeping discus and I had a question. Are the brilliant turquoise discus stunted? I do two water changes a week and feed twice a day. Flakes in the morning and beef-heart and bloodworms in the afternoon. They share a 75 gallon with a ropefish, 3 bristlenose plecos, and 2 kuhli loaches. I have not seen any growth in the brilliant turquoise ones and I am starting to get a little concerned. I also don't know if the pigeon bloods are where they need to be growth wise, I got them at the same time. Any advice is appreciated.
Thanks!