On multiple occasions when transferring young adult as well as adult male guppies from a larger tank (say a 20 or 10 gallon tank) to a smaller tank (say 10 to 5 gallon tank), they appear to have bladder issues or will just lay on the bottom. If moved back after just a few hours, they seem to recover rather quickly. However, if left longer some have been permanently effected. My acclimate procedures usually cover 36 minutes, so am wondering if it is just the downsizing of water volume or tank size or something else? Appreciate any comments. Thanks