Baby rats tend to get along better than when the rats are adults.
How you could go about it is keeping them apart for a 3 week period to make sure they don't infect each other with any potential illnesses and also to help settle the new little one in the home and its new smells and sounds. After this period, you can take both of the rats to a neutral area (such as the bathtub or a different place the older rat hasn't claimed yet) put down a towel and some treats they both love and just let them get to know each other. Keep a close eye in case they get into a fight. They can fight a bit to establish dominance, but you just need to keep an eye out that things don't get terribly out of hand and fur starts flying. Keep this up for a few days, letting them sleep in their own cages at night. After the neutral area you can carefully put the new rattie in the cage with the older one and keep an eye on it there. Let them still sleep in their own cages at night for now. It might help to re-arrange the cage right before you put the new rat in or completely clean it and all the toys in it so it doesn't smell too much of the old rat. It could help with territorial issues.

There are other methods to introduce new rats to each other. This is advice I've pieced together from different forums and videos but I haven't had the chance yet to put these methods to the test. From what I've gathered these are tried and tested methods and they work most of the time, but it'll depend largely on the rats themselves.

You can always search forums yourself for "Introducing baby female rats" and see what pops up.

Best of luck!

Wow thanks a lot for all this info c:
Thank you!!!

No problem, hope everything works out for you!

I use to breed rats <3 dumbo ones at that! :D

I liked introducing them between two cages pushed up beside one another for a little while, they'll hang on the side and kinda.. smell at each other.

All in all the person above gave pretty good advice! <3

Yeah that's what I was thinking!!

Well you slowly lower the bag into the tank so the water can get to the proper tempurature, this gives the creatures to eye eachother up---waitaminute

xD what the above said is right on! Good luck with your rats! Pstakepictures ivi

So funny x) Your comment made me laugh!

OH MY

:D You'll have to upload a picture of your new rats soon

That sounds so cute!!!

I hope they will get along and snuggle with each other <3
Rat snuggles are the cutest uvu

Try putting them in a neutral territory first, see how they react with one another, then if all goes well then it is okay to put them together?o:

Yeah that's what I'm thinking :>

Have fun with your little ratties! <3
They are seriously like little dogs. owo Not sure if you have had any previous to these ones... but yes. They are so loving~
;u; Owner of rats for about 4 years, going on 5.

Teenie tiny dogs

RATTIEEEEE

pics
pics
pics
pics
picspicspicspics

LITTLE BABY
There some pics of her on my twitter and videos on vine :>

throw one at the other and chant satanic words at them

That only works for me with other people tho

I kno its how u got me bb winks

scares the shit out of you
becomes friends

tru frens

I wouldn't be as worried if the dumbo rat wasn't a baby ;w ;

Ive had and bred rats (12) from normals, fancy's and dumbos. females might spar if older but usually quite harmless. though if younger should not be an issue whatso ever. though i recommend you introduce them in a clean neutral space that doesnt smell like either rat. they will probably touch noses and mostlkely ignore eachother from there untill they are cage mates. let them run around for 30 mins and then see how they do in the cage together

the only reason i dont recommend letting them introduce through the bars is i had one female reach through the cage bars and rip another females ear. but again this was a one time issue.

Will keep this in mind!!

just put them in separate cages in the room for a while to get used to each others noise and scent, and start placing the cages closer a little bit at a time (moving them closer every 2 days?) and maybe take them out with a trusted friend so you can both can handle one rat and have a close watch on what they do c: