Scratching Blue Ram

[Waterloo Kid]

I'd appreciate a little guidance regarding one of my Rams. I have had two Blue Rams for two weeks now. To start with one was the boss with the other playing second fiddle. After a few days the rolls reversed and since then the 'lesser' Ram has been getting more subdued. He (I think!) is also starting to repeatedly scratch himself on rocks/plants/gravel. It's always on the right side of it's head near the bottom of its gill cover. He is now starting to hide away more than he used to.
I assume that he's got some sort of parasite or gill fluke. His appetite seems OK.
Here are my questions:
1/ How can I be sure what's wrong?
2/ I don't have another tank so can I treat him in with his tankmates?
3/ What's the best medication to use?
4/ Should I use salt?

Here are my details
400 litre tank
Ammonia 0
Nitrite 0
Nitrate 10ppm
pH 7.0
GH 4 degrees
KH 2 Degrees

10 Zebra Danios 10 Glowlight Tetra 10 Neon Tetra 2 Dwarf Gourami 2 Neon Rainbowfish
2 Blue Rams (including my problem fish)

The tank is six weeks old and I am going to make my first 25% water change tomorrow (what else are Saturdays for?). Should I have done this sooner even though the water chemistry is OK? This is my return to fishkeeping after about 15 years off and so much has changed! I'd be grateful for some help and wisedom from you guys and gals out there.

Ta,

Waterloo Kid

 

[bodyshop20]

I have balloon rams,and Dutch rams, you call them blue.
I think you have a gill fluke, well your fish not you,
Just treat them for gill fluke and i think you will be ok.