If you have no other tank space available, perhaps the store will take the gourami? Some stores will take fish in exchange (or even give it to them, considering the trouble it is causing it would be worth it).
Or the last resort, destroy the fish. I have had to do this; sometimes even "peaceful" fish can turn nasty, as Inga said. You have to consider the whole picture; you have 4 angels that are being hounded and stressed, and they will more than likely succumb in time. Removing the culprit is the best cure for their long-term health and survival.
My next comments are not intended as blame to you, but just general comments to those reading: This is exactly why I so often encourage members to read the fish profiles before buying the fish; "normal" traits are usually mentioned, and while there are always exceptions, the "normal" is most likely going to occur eventually, so this has to be considered before getting this or that fish--if it happens, can you deal with it later? If not, avoid the fish.
Last edited by Byron; 10-25-2010 at 04:09 PM..