I think I see a (if not the) problem. If these fish are in a 10 gallon tank, they need to be returned to the fishstore. A 10 gallon tank is not nearly large enough for any one of these fish, much less all of them. Unless you plan to rehouse them in very short order. Also, has the tank been cycled? Or is it a new setup? If that's the case, the fish may be suffering from high ammonia and/or nitrates. Get a test kit and test for these two toxic substances.
\Dan