and, friend... I would advice you not to apply any treatment to this fish, nothing can help unless you return back them to the original water.

This is my best advice upon long distance deliver, collect extra original water and always use the biggest plastic bag to keep the fish in minimum stress. And, don't immediately introduce the fish into you new water, you have to keep the fish in the original water and slowly introduce new water into it. When I say slowly, mean that you really need to take two or three days to do it.. After all, I shall assure you 90% safe of the fish, the 10% left is your new water condition and how you work on it to maintain. Ok!

And one more thing, please check water temperature as well.. remember, tolerance allow is +/-2, temperature, pH, kH, and so on..