Getting a bigger tank

[Irishdancer]

So after seeing this forum, I realized that the tanks I had for my fish were too small. I've already replaced the one for my newer fish, and I'm going to replace the other one this weekend. My question is this: since my fish has been living in a small tank for more than a month, will it be stressful for him to suddenly be put in a tank more than twice as big? And if so, is there anything I should do to make it easier for him?

[Harley]

I recently went through/am going through this. Harley was in a 1 gallon bowl and then after being on this site for a while I decided to get him a heater, filter and more room so I moved him into a 10 gallon. He was in the 1 gallon for about 10 days and previously lived in about a 1/4 gallon container at the pet store. He was a bit cautious for the first day or so and was always checking things out and kind of poking around. Now that he's been there for a while (3+ weeks) he's much more used to it and swims around like he owns the place. The only change is he used to make bubble nests every other day and he's yet to make one in his new home. Most people here said not too worry about it too much, he may still do it again in time. As far as comfort goes I would make sure he has plants or other decorations and ornaments to hide out in/around if he wants or needs to. Other than that just keep on top of the water chemistry and I'm sure the betta will adjust fine in time.