Today I finally bought 2 gerbils! They're both males. The black and white one is named Moe and the grayish brown one is Louie. In the pet store, I was looking for a small waterbottle for my 10 gallon tank, but the small ones were sold out, so I ended up buying a longer one. I set up their tank and realized that when they start to burrow in it, the tip of the waterbottle might get covered! Should I try to find a shorter one, or will this be ok?