How long has your tank cycled?
what kinda filtration do you have?
What type of tank are you wanting to set up? i.e.(aggressive, community, reef)
I think we need a little more info before anybody can make any "GOOD" suggestions.
Are you using a Dual bio wheel for a 100G tank? If so before you buy fish you should spend a little more money on filtration. You could add some small fish now but you will save yourself numerous headaches by investing in more filtration. At minimum a second dual bio wheel system.
NOT <img src="graemlins//urrr.gif" border="0" alt="[urrr]" /> <img src="graemlins//urrr.gif" border="0" alt="[urrr]" /> <img src="graemlins//urrr.gif" border="0" alt="[urrr]" /> <img src="graemlins//urrr.gif" border="0" alt="[urrr]" /> <img src="graemlins//urrr.gif" border="0" alt="[urrr]" /> what type fiilter should i change it i can go to my friends fish shop and he can give me one for free