I can't tell from these pics but she's either giving birth or it is a prolapsed rectum, which could be due to Hexamita. Which if you had this fish for only a week it was probably already weakened... if it is still there now you can give her an epsom salt bath, keep up water quality and feed live/frozen foods or try to find food medicated with Metronidizole... though it is important to note these are all symptoms, not causes.
