What I have done is just draw a 5 gallon bucket full of fresh water, with an airstone, and let it run until the temps match. Then, dip each fish in there one by one with a net for up to one minute depending on the size of the fish and how stressed they get. Repeat the process for each fish. When doing the lion, use a large glass bowl with minimal tank water. This will not harm those beautiful fins or your unlucky hands or fingers. Place the bowl near the surface of the tank, and slowly herd him in with the net. Its tricky. The main thing is to be calm and move with slow deliberate movements. It reduces the stress for you and the fish. Go ahead and dip the damsels anyway, the can live through anything and better safe than sorry. I would not advise this on the eel though. I havent heard of this being done on a moray. They are very disease resistant and when my rays had a parasite infestation, the eel is the only one that didnt get it. The life cycle of ich is probably well known by now to everyone. Just because the spots are off the fish, they are still in the tank. If possible, remove the eel to another tank and treat with copper in LOW doses with decorations, rocks, etc. removed. Do this for about two weeks and then use a copper test to check levels and insert the eel when it goes down. Not fun. HTH, good luck. -Gas