Have you cycled your tanks? Please check out the link in my thread...it explains the importance and the process.
Since you already have fish, you're going to need to do a "fish in" cycle. I'll try to find the link.
Do you have a test kit? If so, what type? Your should go do a large pwc
(partial water change) immediately. Make sure you use your dechlorinator when you do it.
I'll be back with the link.