| Welcome to the forum! Sorry to hear about your problem though. I am sure you can get some help from the people here though as there are tons of very knowledgeable and experienced aquarists checking in every day.
First, there are a couple types of fish that would fall under a common name 'pearl scale'. Do you know if it is a gourami, goldfish, angelfish, etc....?
I would be suspect of this store for selling you a fish that required splashing on top of the water to get it to move around. This is usually not a good sign. In the United States, or at least in my area, most times I buy freshwater fish that are guaranteed for about 7 days but some would require a water sample, usually to prove to you that your at fault for the death. So, I would suggest you look into your tank a bit more in depth...no pun intended...
How long has the tank been up and running?
Do you test your water for ammonia, nitrites, and nitrates and if so, what are those numbers?
How many other fish are in the tank and what is the size of the tank?
How did you acclimate or introduce the new fish into your tank?
What types of decorations/possible hiding places do you have in your tank?
What types of products or chemicals, if any, do you put into your tank?
Rather than just waiting to see if the fish recovers, I would do a water change to make sure that there are not toxic levels of ammonia, nitrites, or nitrates in the water. I would also turn off the lights in the tank since this could help reduce the stress on your fish and allow it to recover easier on its own. I think with a bit more info like the answers to the above questions would really help narrow things down and help people on this site to give you a more accurate guess as to what the problem could be and how to avoid it in the future. | 
Pearl Scale 
