Actually, it was a pretty good sized bowl (2 gallons). He lived for four years, and until the very end he was very interactive with people who stopped by ”his” desk. His owner had kept bettas before and the one before this was six when he died. *I* kept bettas in a filtered, 3-gallon sun tea jar with a spigot (which made cleanings a breeze-even let you draw out water from the bottom, which is almost as good as a gravel vac) with a little crab heating pad which kept the temp around 78. I never had one live longer than hers, so I wasn’t about to preach at this lady.
Anyway, nobody answered my alder cone question and eventually this guy’s eye healed on its own. They changed things around at the assisted living and his owner got a different desk in a different part of the building. Something about the change disagreed with him and he died shortly after the move.