I would wait on the other fish to put as little stress on the clowns. My current clown has an intestinal worm and I am medicating seachems metroplex. Do you have a QT? If not you can bind the metroplex to food with seachems focus. The ratio is 1:1 with the 2 medications. It says 5:1 (focus to metroplex) but they have updated their site.
Mix the ratio to your food (figure out correct amount by looking at the directions on the back) and add a few drops of water to the mixture until it turns into a paste. Let it sit for 30 minutes and feed. Make sure to feed a little bit at a time and try to feed just so the infected fish will eat it. If other fish eat it it won't hurt them. If you can feed it all in the next 24 hours keep it in the fridge but if not you can freeze it. I like to make the mixture in a shot glass. And by the way, it says that you should only feed it to fish but it should not hurt the inverts but to be safe make sure just the fish eat it
I am not sure if it is contagious but this medication will help all the fish.
Hope this helps.