I just bought 4 new fish from a local seller that I always buy my fish from. All but one made a clear transition from seller to bag to pond. One seems to just be swimming at the top and every now and then sticking its mouth out of the water. I never had a fish do this before could it be its just getting acclimated to the new water conditions? It seemed fine in the holding tank when we bought it. All my other fish are doing fine. Water conditions are fine also. thanks for any assistance