By saying your water params were suited to the fish makes it sound like you have been screwing around with changing your water. If your adding things to change the water chemistry DON'T DO IT. Its best to leave your water alone as it is, the only time you add things is when you need to remove cholorine. Your acclimation method may also be causing the prob by putting the fish through pH shock. You should always slowly add your own water to the water the fish came in to let them adjust to it and not just the temp, the only time you wouldn't do this is when the fish have been shipped to you. Telling us your water params are fine doesn't tell us squat, for all we know your just looking at the tank and seeing is clear and not cloudy so that constitutes it being fine to you. Test the water, pH, ammonia, nitrite, nitrate and give us numbers. If you don't have the test kits for those its time to buy them. Those 4 test kits are an absolute nessecity when dealing with fish, and your first line of defense.
Tono, after two days of being in the tank, this is NOT normal behavior.