Dying fantail

Dying fantail, up-side down on bottom of tank for five days, and
breathing hard. I've changed the water twice, added 2 g salt each time
to a twelve gallon replacement to a 20 gallon tank, and added a teaspoon
of anti-ick medication, although there is no sign of ick. There was
initially a sheen on the water, like oil. I've no idea where it came
from, and that prompted me to exchange some water.

Any ideas?
--
"Fascism should more properly be called corporatism because it is the
merger of state and corporate power." - Benito Mussolini.

http://news.yahoo.com/s/ap/20100119/...ting_activists
http://www.democracynow.org/2010/1/19/headlines