I bought a 7 week old male rat a few weeks ago from a pet shop that I just learnt do not take good care of the pets they stock. My little rat is becoming more social and friendly towards me as the time goes on, but he is still terrified of my older rat whom I have had for over a year. I have researched all the ways to introduce male rats and have followed all instructions, but my new rat is just too scared of the older one to even allow him to go anywhere near him. This is really frustrating seeings as I do not want to have two separate cages for ever. I bought this new rat to give my older one company, and the fights and terror is not helping what so ever. Can someone please give me any ideas on how to make my little rat more tolerant of the older one?