I tend to agree, that while I think 5 gallons and up is best for a betta, one can live okay in a 1 gallon provided that it's properly cared for. Including regular water changes and proper heating, to ensure overall health.
Just from personal experience, when I moved Tofu from a 2 gallon bowl, to a 5 gallon filtered and cycled tank, he became a whole new fish. He became lively, and active, and just seemed... happier.
TeenyTiny, you said yourself that once you transferred your betta into a larger 5 gallon tank, he "was a whole new fish", all in a positive light. That's the main deal between the safe 1 gallon and a safe 5 gallon: the "change" in the fish, the activity in the fish, etc... But really, what is our definition of "thriving" for a betta? For me, I don't use bubble nests as an indication of thriving. Would "thriving" be being able to swim ALL OVER? Or would it stop at having absolute optimum water clarity and top-notch health?
I think it's a matter of opinion. There's no way of knowing what the fish think or feel (other than by actual illness caused by poor conditions), so ultimately it's a judgment made on the owner's feelings. I agree that good care is the main consideration.
Personally, I had my first betta in a 3 gallon and thought that was fine. They are now in 20-litres and I'm sure they'd have plenty of room in smaller than that, but they seem to use all of the tanks and I like watching them swim all about. Personally, I'd feel uncomfortable with less than 10-litres, but that probably has as much to do with a sense of aesthetics as with the fish's well-being.
As long as they can do a few reasonable swimming strokes before hitting a tank wall I feel comfortable looking at them and feel that they are ok. Seeing them in the shops in the jars where they can't swim around makes me really uncomfortable and I don't like it at all.
With Tofu when he was in his 2 gallon bowl, I kept his water sparkling clean, I did water changes every 2 days like clockwork, and sometimes daily. He was heated, and kept in as good of conditions as you can keep him in.
However, he never blew a bubblenest. He rarely ever swam. He just sat at the bottom of that bowl for months, literally. He'd swim up to eat, and then sink back to the bottom, and he just kind of... sat there.
When I moved him to the 5 gallon, he began swimming all over, he uses every inch of his tank. I have him in front of a window and he seems to enjoy the morning sunlight. He occasionally flares at his reflection, and about 1/3 of his tank is a massive bubblenest. He just seems so much different in a bigger tank.
For me, optimal health and water is important. But if the fish is like Tofu, and just sits there at the bottom and just exists... to me that's not enough. Happiness, and liveliness is another big part. I want my guys to not just be healthy, but to be happy too. And I know people say it's hard to know what a happy betta looks like, but to me, Tofu looks happy now. I see a happy betta as one that swims around a lot, flares occasionally, builds bubblenests sometimes, and just makes good use of his enclosure. Not one that tends to just sit in one spot most of the day and only move occasionally.
Is a very informative thread and I will humbly enter my two cents worth.
I have been keeping fish since I was sixteen and am 53 years young at present. Fishes will always do better in properly heated,cycled,and filtered tanks and Bettas are no different. Five gallons would be the minimum in my view. The problems with smaller tanks are numerous . Poor dilution of waste capabilities between water changes,fluctuating temperatures that are more easily controlled in heated tanks with larger water volume ,Uncycled tanks readily allow toxins such as ammonia and nitrites to affect the fish in negative way due to possible over feeding and waste created by ALL fishes unless water changes occur with proper frequency which could mean daily, depending on volume of water. (Bigger the tank, the more dilution capabilities).
Those who keep Bettas in small, unfiltered,uncycled vases,bowls,jars,or tanks smaller than 2.5 gallons aren't doing the fishes any favors and any book written on proper care of tropical fishes will tell you so.
Fish create ammonia each and every day through respiration, (breathing) and through waste created (poop). without a properly cycled filter,, they are swimming in toxic condtions between water changes on daily basis= sick bettas. This will ALWAYS be the case.
When I began keeping fish, I single handedly murdered untold numbers of fishes through ignorance on the proper care of them. With the information published in books today, and available on the internet,, it passes my understanding as to why ,,,people continue to kill their fishes.
Bettas and goldfish are the most abused fishes in the trade ,and when people finally grasp that 80 to 90 perecent of ALL fish health issues are directly related to water quality ,or lack thereof,, then perhaps providing them with the enviornment needed to ensure their health will become the norm.
But I ain't holding my breath.
"Thrive," without referring to my Webster's, is for the animal to live as high a quality life as is possible. To remain healthy, to have good physical condition, and to spend their days as unstressed and functional as any of their species brethren. For this threads sake just define "thrive" as a place where the betta can live a long life, doing what it is betta's do, in a healthy, growing, unstressed environment. The thread is an effort to "learn" what others do, so as to improve the way we each care for our bettas. If there are "formal" studies with regard to this, by all means, post it! Appreciate those that have posted. Thanks.
In order to thrive, a betta needs good water, proper nutrition, a place to hide, and very little water movement. However you prefer to provide those "ingredients" is a matter of personal taste. A happy betta is a happy betta, and his home is what he lives in.