Adjusting to a new tank can be stressful for some bettas. To help ease the transition you can place your betta in a quiet, low traffic area of your home while he is getting used to his new set up. Bettas don’t hear the same way you and I do but they are able to feel vibrations so try to avoid the thumping of stereo base or similar low vibrations if your betta appears to be skittish. If his aquarium is in a permanent location and can’t be easily moved you can wrap the glass in a towel for the first day or so until he gets used to things. Bettas also love plants and caves. Not only are they an interesting addition to your tank but they offer your betta a sense of security. Help your betta feel protected in his first few days and soon he will be greeting you at the glass, wiggling his tail and begging for food with the rest of them.