I currently have a 55 gallon tank which I plan to stock with only angelfish and a cory or two. However, I have a growing fascination with Bettas. Since I don't want to mix a betta with the load I will have in my 55 gallon, what size tank would be appropriate to house a betta? Those tiny bowls they have bettas in are absolutely atrocious. I want something bigger but not too big, but something where the betta could be 100 percent comfortable.