Of course you are, I didn't doubt.
I had been reading somewhere the some goldfish can live 20 years so I wondered if he was one. That's quite a long life for a pet! My cat is 19. Time flies (or maybe in your case, swims?) 8 inches is a good size too. I had a 45 gallon at one time for a turtle (modified- the tank not the turtle) and it's a good size, would that be big enough? Does he recognise you?