The problem I have is my female crowntail always has stressed (horizontal) lines on her except for after she eats. She is in a 10g tank with 2 veiltails. No nipping or chasing. They are just fine together. They get along. I did 100% water change a week ago. She is healthy as far as I can tell. Could she have a parasite or ulcer that would make her stress marks go away after she eats? What can I do to get her to stop stressing or get rid of what ever is internally wrong with her? Please I need help.