White spot on Clownfish in mature tank
 

A little over a month ago one of our Clownfish started getting a single white spot or two on it in random locations (fin and middle of body). The fish has been fine and it was always hard to tell what it was. Today I was able to get these pictures. They almost seem to be kind of worm like. Nothing has been added or changed on this tank in over a year and none of the other fish have any spots including the clowns mate who it's always nudging. Any idea what I'm dealing with? I'm guessing a parasite of some kind, but how the heck did it get in the tank? I'm thinking it's not Brooklynella as it would have killed it by now and lymphocystis would have resolved itself?

http://i.imgur.com/2bVOdqY.jpg
http://i.imgur.com/Dbcd3XZ.jpg

And now it's gone again, so whatever it is, is using my fish as lunch. Ich? Although it looks kind of big for that?

It doesn't look like marine ich from the size and shape of that thing. Most likely some kind of parasites. I would try fresh water dip first. Google the protocol or let me know if you want the details.