Yesterday my betta was happy and building bubble nest but he was only in a 1 gallon tank so I thought I would give him an upgrade to a 5 gallon tank. I changed almost everything because everyone said sand was better but I kept his bubble nest. At first when moved into the bigger tank he was swimming and eating, but then 10 minutes later he stopped moving at the top of his tank. he usually loves his house but now he won’t go near it. I don’t know what’s wrong can someone help?
