Single rat

Question
I wanted to get my 20 week old male rat company (1 of his siblings) but will they get into conflict? I got him in December and thought he'd be okay on his own but he's still really anxious so I thought maybe I should've got two in the first place. I know that especially with males introducing another male can cause conflict - but I thought that if it was one of his siblings then perhaps they would get on and this wouldn't be the case. Any information that would help the situation would be greatly appreciated.

Answer
You are correct.  Its always best to get more than one rat at a time as they are very social animals and experience lonliness and sometimes even depression when alone.

It is never too late to get a companion for your boy.  However, at this point it doesnt really matter if you get his brother or another boy close in age, as he and his brother have been removed for a long enough time, i assume, that they may not remember each other.  Although it is possible they make adapt to each other easier if they are brothers.  You will still need to go through the standard process of introductions.  In some cases, these go super smoothly, and in others, it may take time and patience on your part.  In most cases either way, rats eventually learn to live together.

However, I strongly recommend getting him TWO friends, not just one, and i will explain why.  If one should unexpectedly and suddenly die in the future, you would once again be left with one lonely or depressed rat, and find yourself scrambling to find another boy close in age quickly, and there might not be any avaialble.  If you always keep 3 or more rats at one time, then when you lose one, the remaining ones have each other, and at that point, you always need to add one more, and go through introductions again, but it is well worth it.

I will give you links to a couple of trusted sources with detailed introduction steps, which i agree with and myself follow specifically myself when doing intros.  You will notice similarities between the two websites as far as intros.  Take note of the information regarding quarantining, which may mean an additional 2 to 3 weeks of your boy being solo.  To avoid having to quarantine, you can adopt your new boys from a reputable breeder, whos rats come from a clean, germ free environment, and you also have the benefit of getting much healthier rats then you woukd from a pet store.  Some rat owners dont have the time or the proper facilities tomquarantine and just put new rat with existing rat.  If you do this, just be aware that you may put your current boy at risk.  The most common contageous illness brought in from outside rats are mycoplasmosis related infections, so look for sneezing, wheezing or chirping like sounds from your boys.  If you see this, they all need to visit the vet for antibiotics.  Make sure you select a vet with experience in treating rats asap, if you havent done so already.

http://ratguide.com/care/behavior/introducing_rats.php
http://www.ratfanclub.org/newrat.html

I wish you luck and success in your future with pet rats.  Should you need any advice whatsoever, pleas write me!