Alright, we just keep repeating the same thing over and over.
You need to realize that your tank needs to fully cycle, and the water changes are not a quick fix! Changing the water 1 time will not fix your problem!!
Do water changes 4-5 times a week, check your levels on occassion, and eventually it will be cycled! As I said I have seen this take anywhere from 2 weeks up to many months!!
I'm not trying to be rude, but stop asking if you should do a water change, stop asking if it will help, read the 6 pages of advice and just do it! If you have ammonia in your tank (no matter how minute), if you have nitrite in your tank (no matter how minute) it IS harming your fish, and they WILL keep scratching/flashing/etc because it is burning them!!
Keep up the water changes, and eventually it will even out!!!
PS- I really am not trying to be rude, and I realize at one point we are all new to this, but please just read the advice and follow it!!!