You can dip your coral in fresh water. Make sure the alk, ph, temp, is as close to the tank water as possible. I rarley dip mine. If you must dip it I would only do it for 15 to 30 seconds and only once.
I collect hermits from the beach and dip them for about 10 min. This kills most of the bryzoans and hitchhikers on their shells.
Why do you need to dip the Purple Pseudochromis?
If you need to dip him do it the same as for the coral. It is a good idea to run an air stone while dipping fish. If the fish is not stressed leave it in the water 5 or 6 min. If the fish shows signs of stress remove it right away.
I'm sure others have diff methods. Good luck.
Andy