My guess would be more likely it is jealous of the new one.
Give them both time to adjust to each other and make sure to
also give each of them equal loving time with you.
PS I have 2 DYH Amazon who are the same way. Only they have
hated each other from day one. Both get jealous if I am
holding the other so I always tell them "your turn next". I
seems to work. Hopefully yours will get along someday.