OK, let's back up a bit...
Is this a fish-only tank with artificial decorations and/or dead
coral skeletons, or does the tank contain live rock too? If it does contain live rock, I'm afraid copper would have ruined it.
Did you treat the fish in the main tank, or in a hospital tank? Did you (or your friend) test the copper level in the tank, and did you treat for the recommended duration, or was it a one-shot deal?
Copper can be effective, but it's toxic. Toxic to the fishes, as well as parasites. The "trick" is to poison the parasites without poisoning the fish (much). It is imperative, when using copper, to use an accurate test kit to monitor the level of copper in the treatment water. Too much will poison the fish, and too little will be ineffective. It's also important to remove the copper as much as possible, after treatment. I have experience with Seachem Cupramine (I use it occasionally in my store's system), it is effective but not as toxic to the fish as other types, and it's easily removed with either carbon or their companion product, Curprisorb. Polyfilter (brand name) will also remove most forms of copper, as well as other medications. Do NOT re-dose the copper until you test for the current level of copper, as you may end up overdosing and doing more harm than good.
Do you know the brand name of the treatment you used?
Respectfully, as the keeper of the tank, it is your responsibility to educate yourself on proper care. Coming here is a good start
So I'm not flaming you... call it gentle encouragement to not rely on your friend quite as much, but rather, inform yourself so you can take care of your creatures properly and avoid problems such as this one. I'd recommend reading, "The Conscientious Marine Aquarist" by
Robert Fenner to start.. it's a good book, easy reading and covers most of the topics and issues that you'll encounter. (Lecture mode: off
)
Now, back to the problem at hand. You mentioned the Humu is a newer addition, and he appears to be scratching, so it's possible he brought the problem into the tank. Look at him closely and tell us if you see anything on the skin.. bumps, spots, abrasions etc. Look at the fish's eyes - clear or cloudy? Anything that might give us a clue about what is wrong. Are the fish eating well? How much are you feeding them and how often, and what are you feeding them?
You could try some garlic added to the food, it will boost their immune systems, stimulate their appetite and this has anecdotally been shown to help relieve parasitic infestations.
Again.. any more information you can provide will help us to help you
Jenn
