Help: New Butterfly with Ich. FML.

[ScubaSteve]

So yesterday I picked up a longnose butterfly from another member. Brought him home, got him set up with a nice long acclimation and watched him for several hours. He was happy, perky, eating like crazy and not showing any signs of distress. Best of all, he was a perfect specimen with no signs of anything. Seeing as how I don't necessarily have the space for a quarantine, observation is really my only option.

I made sure the lights were off when I added him to the tank and there isn't anyone there to harass him. My blenny checked him out for a bit then left him alone. The butterfly seemed happy enough, zipping around my tank demolishing every tube worm it could find, ate some more mysis... all was well! It seemed fairly awake at midnight last night... I assume just having trouble the first night in a new tank.

Well, I woke up this morning and BAM!, f***ing ich on the new butterfly. F*** me! I'd call it a moderate infection.

So, I've never had to deal with ich before as I keep my water clean, don't stress my fish, avoid the ich-magnets and well.... I've been lucky. This guy is in a full reef so I can't treat the tank. I've been reading about all the different options and don't necessarily see a solution that is going to work for me, aside from building a quarantine (really, really not the preferred option right now).

What should I do here? Advice please.