Gerbils How many should I have?

Currently I have a 20 gallon aquarium with a wire size tank Topper self. I wondered how he could many gerbils live there, with not more crowded? 2.3?

I might try three, but could be a big risk. Not the fact that the size of gerbils in general. The first time I bought my gerbil had only about a year or two, but then decided to get another. We have another, because we researched this, and almost all said sources extend the life of a hamster to have a partner. When we went to the pet store says the guy who wanted another gerbil for the convenience of our first said he could not function. He said he would fight and kill each other to death. But I think we were lucky because it turned to how each one of the brothers and developed. I only recommend getting two gerbils, and if possible from the same litter, because that way you do not fight. 3 could obtain be risky, especially if they are from the same litter. Hope this helps!

Rita and Dori, my new baby gerbils