The only way to completely cure the fish as well as keep it from getting it again is to quarantine it and use one (only one) of several methods of curing ick. Copper and hyposalinity are the most popular. The fish must be in quarantine for 6-8 weeks to ensure that the full life cycle of the ick has run its course as several of the preferred methods are only effective when the ick is in the free floating larvae stage of its life.
The display tank needs to remain fishless during this time (6-8 weeks). Ick must have a fish to host. When the eggs hatch into larvae without fish to infect they will die.
The quarantine should be bare bottom with minimal porous surfaces with adequate filtration (not carbon) and water movement for the fish. All new fish should be quarantined to ensure that they are healthy before introducing them into the display tank.
It would be in you and your friends best interest to read both articles entirely before deciding what course of action to take. After you have decided be sure to use only that method and finish the treatment completely before introducing the fish back into the display tank or you will risk re-infection.
Roblack is correct about UV being able to help control outbreaks of Ick; however one would need to research the correct amount of flow through the UV sterilizer to do the job. This would not be a universal GPH either; it would depend on design of the sterilizer and the wattage of the UV bulb.
For instance the Turbo-Twist UV Sterilizer recommends the following:
Model 9W, Flow Rate for Parasites - 55 gph, Flow Rate for Algae - 121 gph, Flow Rate for Bacteria - 253 gph
Model 18W, Flow Rate for Parasites - 110 gph, Flow Rate for Algae - 240 gph, Flow Rate for Bacteria - 500 gph
Model 36W, Flow Rate for Parasites - 290 gph, Flow Rate for Algae - 680 gph, Flow Rate for Bacteria - 1550 gph
I would consider a UV sterilizer more of a maintenance tool, not a curing tool.
i have tried everything aand garlic dosnt work at all . but i seen when ever it trys to break out i feed them more and bam!! it goes away. i think its because fish get so happy when they get feed so the stress goes away
Isolation is fine if you have the ability to quarantine the tank but I've had ich get pretty bad and ridich is reef safe and did a mediocre job at bringing the outbreak undercontrol until the fish naturally fought off the parasites, a 3 minute freshwater dip works good for fish who are actively eating. I've had great success in the past with dips and ridich