White Adipose Fin

Hi, one of my Congo Tetra's and one Sterbai Cory have a white Adipose fin. I think the Congo may have always had it but I don't recall seeing it on the Cory. Both fish seem happy and normal and there doesn't appear to be any fluffiness, although as they are both fairly timid it's hard to get really close for a better look. Should I be concerned?

Thanks