I just recently upgraded my tank from a 10 gallon to a 40 gallon and ever since I have been having a few problems; the water will not stay clear and my fish are starting to get clear white slime coats all over their body. Before putting my fish in I let the tank cycle about 3 days. I took the water in to Pets Mart and everything tested fine. Once I put the fish in (4 med. goldfish) the problem with the fogginess of the water began. Now it has been about two weeks since the fish have inhabited my tank and yesterday when I went to feed my fish, I noticed my black moore was cover in a white slime coat. He acts fine otherwise and is active. What is this? Could this be from growing? I have been using spring water in my tank and I did a partial water change after the first week (about 15%). The gravel in my tank is a natural almost crushed gravel. I thought that it may be contributing to the cloudiness of the tank because of the fact the rocks are crushed so fine and were really hard to get clean. I have also thought about getting a second filter, but wasn't sure if two filters would make a difference. I have a Penguin Bio Wheel right now. Any help you may be able to provide on this would be greatly appreciated!

Your tank will not have cycled in the three days prior to adding your fish. The cycling process usually takes between 6-8 weeks.
The cloudiness you are experiening is a bacterial bloom because your tank is just starting to cycle, and this cloudiness will vanish once the cycling is almost complete. When you tested your water the readings would all have been fine because the fish hadn't been in the tank long enough for any ammonia or nitrite to form.
The extra slime on your fish is almost certainly being caused by high levels of ammonia or nitrite so you need to get your water tested pretty quickly. This problem will be made worse because you have 4 fish in the tank who will be producing much more waste than 1 or 2 fish. You really should add fish gradually because even in a properly cycled tank there can be a small spike in nitrites whille the bio-bugs become accustomed tot he extra waste. Slime can also be caused by fluctuations in PH so you need to keep an eye on this too. As long as it remains constant leave it well alone, but if you are experiencing fluctuations then you will need to do something about it.
For now start daily 30% water changes (temperature matched and dechlorinated) and cut your feeding right back to a couple of pellets for each fish once a day. These steps will help stop levels rising anymore and should start lowering ammonia and nitrite, so making it less toxic to your fish. You will need to keep up these water changes until your ammonia and nitrite are at 0 and your nitrates are over 0 but preferably under 20. That is when your tank is properly cycled.

Thanks for responding, I did a 10% water change last night and I will do another 20% tonight. I think I am also going to go ahead and buy another filter since there are so many fish in there.