Will gerbils fight with each other?

It's possible and very probable that they will fight if you just throw them together, yes. Gerbils are social animals but ONLY within their family groups. Put a new gerbil in with a group (or two new singleton gerbils together) then chances are they will not accept the newcomer and will fight. Possibly even to the death.

But that does not mean they cannot be housed together. Split cage them and do a proper introduction. Takes about a week, usually, but well worth it. Boys are easier to work with than girls (gerbils are a female-dominant species so boys are more laid back and accepting) and if one or both are youngsters then you're pretty good to go for a successful introduction.

Here is a little bit more on split caging:

http://agsgerbils.org/Learn/Gerbil_Care_Handbook/a...

http://www.gerbilsbyleigh.com/guide-to-gerbil-spli...

http://www.twinsqueaks.com/tips.php

http://hhgerbilry.com/splitcage.html

at first if you just shove them together they will un till death so this is what me and my friend to help introduce my two girbils ( we didn't know what we had a to do we just started it and it worked perfectly)

first he held back there claws and let them sniff each other for a few minuets

get used to each other for about a week then

we let them play together but watched very carefully

then started to swap their cages round every now and then for about a week or so , so they could get very used to their sents

then let them in the biggest cage just for about an hour or so we did this for a couple days then we let them stay with each other for longer and longer

then we left them for a day they were fine 2 days fine then we left them for a week ( still watching very carefully )

then they were fine they live together very happy :)))