Sick Goldfish?

Question
Hi, I am not sure if my goldfish is sick or not.  I have had my aquarium for about 4 weeks now - it holds 120 litres of water and I have 3 goldfish in it.  Two of the goldfish are fine but one of them seems to be out of sorts.  He is quite inactive and seems to stay in the one spot most of the time.  He is still feeding though and is normally first to the top of the aquarium when he sees me there.  The ammonia level is 1ppm and the PH is 7.  Both Nitrites and Nitrates are zero.  I know my aquarium is going through the cycling process at the moment so that's why the ammonia levels are up but considering the PH is at 7 I would have thought an ammonia level of 1ppm would not be harmful to the goldfish.  I do regular water changes to ensure the ammonia levels don't surge.  The temperature of the water in the aquarium is room temperature.  Is it normal for some goldfish to be quite inactive?

Also this particular goldfish has black marks on him, under his belly and under his chin.  I think it's from the previous aquarium he was in where the ammonia levels may have been high.  I thought the black patches would have disappered by now but they have remained.  Could this be pigmentation?

Please help.

Answer
It could be he is merely adjusting to the new conditions. The black marks do not worry me (if they were red on the other hand....). The black patches could simply mean he is changing color keep an eye on the patches and see if anything is coming out of there