Went to check out the tank this morning, and noticed my ywg swimming in circles. Looking closer noticed he had faded quite a bit since yesterday. What could be the problem? I have a tiger pistol in my tank that took over the gobies home, and won't let the goby in now. He keeps snappin at the goby for like the past week since I got the pistol. Do you think that the goby is stressed by the situatio? What can I do to encourage the two to pair?" which I thought they did as soon as the pistol moved into the goby lair"but was wrong I guess.

What's with the " usage?

Params? Other fish/corals ok? Any info at all about your tank?

pairing just sort of happens, just hope for the best or possibly just re introduce them at the same time (ive heard that works)
also, fading color from yellow to gray is indicative of you having a female
females have a tendency to loose color.

check your params, make sure its getting food and try to find it a new spot to hang out.

Do you have a picture of the pistol? Not all pistol shrimp pair with gobies.

No pics. Pretty sure he's a tiger. Green and darker green rings down his body with a slightly redish head.

Yeah I saw a female at the LFS the other day and it was more gray green than yellow.

the problem is the title "tiger" can be used for more than one pistol species. The shrimp which I had paired with a Randall's shrimp goby was Alpheus bellulus, and I would describe it as brown or reddish rather than green.
http://images.google.com/images?client=saf...l=en&tab=wi

Yes some, not all YWG loose their color and it's not a reflection of their health status unless something else is wrong too. My YMG was yellow for about a month, now 1.5 years later she is light gray with darker gray bands and blue spots and as fat as a goby can get.
I did alot of research on this when it happened.
And some YWG never change color even it they are a pair, so I do not think the sex of the goby has anything to do with it.

My goby got it's color back in the day time. My concern now is the pistol he's mean. Not like a tiger is suposed to act.

My tiger pistol is more of a white and brownish/tan banded. From your description it seems like yours may be a different species of pistol. Tigers, at least what I've seen don't have any green or red markings.

That sux how do I get em out now? He's made him self quite a home in this one rock I have.

Besides doing some type of bottle trap, you may have to remove all the rocks.