Betta

[Giant Danio]

I Know people say a Betta should have at least a 5 gallon tank but I have had my Betta in a 2.5 gallon tank for just over a year now and he is very happy and healthy and blow's bubble nests all of the time. His name is Pepto I don't have very good pics but I do have some
He gets fed 2 hikari Betta bites every day and some blood worms 1 time a week.

 

[Giant Danio]

More pics

 

[KaylNeko]

Not everyone thinks 5 gallon is minimum--the minimum I usually see is 2.5 gallons. What most people get tetchy about is whether the water is at the correct temperature of 78 to 80 or so since they are a tropical fish, and if it's filtered or getting changed often enough so they're not sitting in ammonia.

 

[Koikid88]

I Know people say a Betta should have at least a 5 gallon tank but I have had my Betta in a 2.5 gallon tank for just over a year now and he is very happy and healthy .

and that's what everyone says too, he is happy and healthy.
In your case, being in a unheated, unfiltered bowl, that's great having him for a year, but he most likely won't see 2. In an actual tank, they live 5+ years.
From those pictures, that looks like 2.5L, not gallons, in comparison with the betta. So he's really in less than 1gallon.

 

[Snowfire]

I was looking on amazon for a small Betta tank and there was one which was 1.5L!! How could anything live in that?
I'm going to get my Betta today, he's got a 25L tank all ready for him