Xenia doesn't travel well. Its not unusual for it to go into shock when moved. The biggest problem with Xenia in a nano is light. Its almost 100% photosynthetic and most nanos don't have enough light for them. Just keep an eye on them. The other thing I would do is check the pH. Xenia like a high pH and as a matter of fact they act like a natural pH meter. The faster they pulse, the higher the pH. Also check your alkalinity. Chances are if the pH is low, so is the alkalinity.