I have a GREAT betta story which I will tell in a moment.
I don’t remember how old I was in that story, and there’s no one to really ask, but I’d say somewhere between six and nine, so not terribly young, but young enough to still be unselfconscious. 
Here is my betta story.
I had a betta, once. He was alone for a while, and then I decided to set up a fish tank. So I set up this awesome fish tank, with angels, tetras, neons, gobys, catfish, and others. It was wonderful. I added the betta to it. I know they are supposed to fight, but I figured if he did, we’d pull him out.
He never fought. He was absolutely Lord and Master, but he lived peacefully in the tank for about three years.
Enter one of Mika’s Great Ideas. I decided he needed a girlfriend! So I went out and bought him a female betta, and added her to the tank. Chaos ensued.
In three days, he had eaten Ms. Betta. We found her remains plugging up the filter.
In two more days he had killed and partially eaten almost every fish in the tank.
In a week, he had eaten most of the plants and killed off all all of the fish.
In two weeks the tank was a barren wasteland! He had destroyed it, all for the introduction of a girl. My beautiful angels, my tetras, my neons. All gone. Why didn’t I remove him? Well, for one, i wasn’t sure it was him, and I was kind of taken aback. By the time my fish were dead (remember that was only five days) I figured he’d be fine now, at least alone.
That betta lived on for two more years. I tell you though, I never put my fingers near the tank again.
Just goes to show what happens when you get the taste! 