Our little Peedie is going on 3 years old. Typically when people revisit our house they ask "Is your fish still alive?" It is like he is some phenomenon. I can safely say he has lived longer than any other fish I have had. Or other water/tank creatures I've had. He is so tough. I've dropped him down the disposal 4 times. (Not while it was running, of course.)
I think another reason Peedie is still here, is his great relationship he has with Lucy. They have spent countless hours alone and Peedie is always left unharmed. In fact, Lucy prefers to get her water specifically from Peedie's bowl. I've never had to get her water, as long as I keep Peedie's bowl clean. She'll watch him, and she won't drink if he is eating. She's very polite. There has only been one occasion- and this is hearsay, that Lucy has ever dipped her paw in the bowl.
I'm not sure the record lifespan of a beta, but I wouldn't be surprised if Peedie goes for the record. He's a good fish.