Hi, I am getting a 2 gerbils for my daughter's bday. I have a glass aquarium i am going to house them in. Tank Measurements Length - 80cm Width - 30cm Height - 40cm Is this tank suitable and big enough for 2 gerbils? Ive been trying to find a topper but with no success. What size of mesh would i need if i decided to make a lid? Hope someone out there could help?