that is a heck of a deal! I got my tank like that, well the tank was new but the water came from my LFS, he was getting rid of one of his show tanks so he hooked me up. watch your yellow tail, I have 1 now(caught the other one), and I used them to help cycle the tank now the entire tank is his and he will terrorise any new fish introduced, I've lost a few because he just pestered them to the point they just got too stressed....I'm still trying to catch him to no avail...I've read that if they are introduced later on, they are fin in community tank but if they are the first fish, they tend to be very territorial which I found out the hard way.