Help!

[asherah]

ok here's the story. 2 of my clownfish were removed from the main tank and placed into an enclosure that was still inside the main tank therefore still have stable water. It was a pump for flow through.
Anyway, these 2 were supposed to be brought back to the store tomororw.
Well I ended up removing the biggest fish because he was so mean to the littlest fish. Poor thing had it's fins all torn up.
But he is now showing little white dots. 3 on his tail. and 3 up by his head.
He is showing no other signs of ich. No scratching no irratic swimming and eating great.
What do I do ?? Should I still take him back to the guy who was going to give me credit for them ? He'd probably have a better chance there...I've never dealt with this. What about the rest of my fish??
Should I pick up some medicine tomorrow ?
Can I use the medicine I have leftover from my freshwater?
Thank you
asherah