I could be wrong... Paddle tail looks pretty normal. Hard to tell these hybrids
Looks like hes stressed. Looks exactly like my males when i move them to seperate tanks. It usually only lasts a few hours. If your ray always looks washed out like that then params are off
I have 3 Henlei's and one of my females does that sometimes. She can be black for weeks and then turn gray for a couple of days. I have near perfect water parameters and I cannot figure it out either. The great thing is she is really healthy so I don't let it get to me too much but I would love to know why only she does it.