my black moor is sick!

Question
I'm not sure what's wrong with my black moor. he lives in a very small take with no filter and i clean his tank out every week. at first he was just floating around at the bottom of the tank. but not his whole body just his head. but when i would come close to the take he would swim around fine. later in the day he seemed to be fine. The next day he was doing it again so my friend thought that he might be constipated. we fed him a green pea. this morning he seemed fine and right now I'm on my lunch and he has white stuff on his skin and is still swimming at the bottom of the take well not even swimming more like floating with his tail in the air. what's wrong with him? is hi dying? and is there anything i can do to fix it?

Answer
I hate to be the bearer of bad news, but your goldfish is very  ill.  Goldfish need a minimum of 20g per fish.  In a small tank with no filtration the water would need to be changed at least every other day and about 70% as well.  Even then, you would be asking for trouble.  My guess would be that you fish is shutting down from ammonia or nitrate poisoning, with a secondary infection (ich or fungus).  You can try treating him for the ich and cleaning the water 70% each day for the next few days, but I can't guarantee any success.