QUOTE(Trinket @ May 20 2008, 04:15 AM)

Well you probably won't like what I'm going to tell you but I can guarantee it is the root of your probs. A 10 gallon may be all-right to house 4 tiny fish for the first few months but over time it becomes a death trap for bacteria. It is very difficult to keep water good and bacteria levels at a safe level in so small a space with 4 growing fish. Pearlscales with their tight packed bodies are especially sensitive to water quality. Your fish have outgrown their home
Is it possible to re-house 2 or 3 of the fish in another tank or rubbermaid? Ideally each fish needs 10 gallons of their own to grow and thrive and stay healthy. If you keep fish in less water volume, over time the toxins build up and the water becomes thick with bacteria. In a cycled tank like this, (4 fish in a 10 gallon) feeding once a day, you would need to be doing 50% water changes minimum DAILY to keep the water safe.
I'm afraid there are no readily available test kits for bacteria build up but your nitrate levels are a fairly good indication of how much at risk you are. Your LFS will test your tank water for you if you take a sample. Get them to write down the exact numbers. Strip tests are not accurate. Better still, invest if you can in a master drop test kit and post back with your levels of ammonia, nitrite, nitrate and pH. These results will tell you so much and help you monitor your water until such time as you can set up a larger tank or tanks for your fish.
Do you think, though, that putting my fish in seperate tanks (or getting a bigger tank) will fix my pearlscale's problem? None of the other fish are showing any signs of difficulty, but, like you sai, it might be because pearlscale are more sensitive to a change in water quality.