ich yuck...

get it out of there...quick. take it back. anything.

 

You may try and feed the tank food with garlic in it to keep up the health of the other fish.

 

There is a reef safe ick treatment I have used in the past. It seemed to work really well, I had to buy it online however. It was on bigalsonline or fosters and smith, I can't remember.

 

You said this is a salt water tank but you said nothing about reef. So do you have corals and other inverts? If not get Coppersafe but make sure all fish are copper safe. I would not trust any reef safe Ich treatments as too many club members have had extremely bad luck with so called reef safe treatments. However there have been people who had luck with such treatments like N3Gen but why risk it.
If you have corals the best treatment is to remove all fish to a hospital tank and treat with either copper or hypo-salinity depending on the if the fish are sopper safe. Then run the tank fallow (without fish) for 6-9 weeks. The length differes based on opinion and the length of the Ich Parasites lifcycle. This is the only way to truly rid the tank of the parasite forever in a reef environment.

 

The other option I reccomend and have used  is what saltwaternewbee mention. I am very convinced that garlic is very effective at combating the ich parasite. If your fish are healthy their immune system can usually fight off the parasite on its own and the Garlic helps this situation. But if the parasite appears to be taking over get copper or hypo-salinity involved quickly.
Do your research, there are a lot of articles on this topic.

 

If you do use any treatments make sure to follow directions. Some, if not most require you remove any charcoal from your filters (if you use) otherwise the medication will be filtered out if you leave charcoal in.

 

if its a reef tank dont use any ich medicine even if it says reef safe its like playing russian roulet trust me i know and i lost

 

I have an unopened container of Ruby Reef - Kick Ich if you are anywhere near the QC and have any interest in trying it...mail ordered for it, but it turned out the fish didn't have ich (never tried the stuff, but it claims to be reef safe)...permanent hostipal/quaranteen tank is the way to go with all future additions!