Puffer secreting slime?

[tennisace]

For some reason, my puffer seems to be secreting some kind of slime or something!
Symptoms:
Rubbing up against things
Spinning
Whenever he hits the sand, it really sticks to him and seems to hang.
Can someone help me? He is my favorite fish and I really don't want to lose him. As far as I can tell, my Maroon Clown and Niger trigger don't have this, but I just combined tanks 3 days ago. I'm not completely sure when this began. My mom says she saw him rubbing before we combined, but I never noticed it. Parasites do not seem to be present, or at least I haven't noticed them and I've looked.
Any advice would be great.

 

[nicetry]

It could be a number of things but parasites are a suspect given the symptoms. Puffers naturally secrete more mucus than many other fish, but the scratching behavior and increased mucus could be ich. Any other symptoms; rapid respirations, redness around the gills, lethargy, loss of appetite? when was the clown fish added out of curiousity?
Do you a have quarantine tank ready to use?
Can you also post your water parameters?
You say you combined two tanks? What all is in the main tank now?

 

[tennisace]

Both are my tanks. The one I have combined into has:
Niger Trigger <

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had him for 4 years
Maroon Clown<

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have had him for 12 years!
Puffer <

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had him for about 1 year
I haven't introduced anything into my tank that would give them ICH or anything. Nothing has been introduced for over 6 months to either tank (besides the combination, but like I said, my mom thinks it started before the combination). I can't see how any parasite would get into the tank.
(Note: When I got the puffer a year ago, it had ICH from the lfs, but I treated it and got rid of it.)