That is a good question Liz and I wish I knew the answer. There is a lot to learn about Discus genetics.
I am going to start combing through what has been published. I just found this and I will read it when I have the time.
AACL Bioflux, 2021, Volume 14, Issue 2. http://www.bioflux.com.ro/aacl 832 Genetic variation of domesticated discus (Symphysodon spp.) 1,2Tian T. Ng, 1Yeong Y. Sung, 1Muhd Danish-Daniel, 3Patrick Sorgeloos, 4,5Yves V. de Peer, 1Li L. Wong, 1Min P