PAHRANA FISH ??

DOES ANYONE KNOW HOW LONG A PAHRANA LIVES? WE GOT CHARLIE 21 YEARS AGO AND HE'S STILL ALIVE.
I KNOW HE'S BLIND IN ONE EYE AND HE ACTS LIKE HE CAN'T SEE AT ALL. THERE IS ONE GOLD FISH LEFT IN THE TANK AFTER ALMOST A YEAR I HAVE TO DROP RAW MEAT OR NIGHTCRAWLERS ON HIS HEAD FOR HIM TO EAT.
HIS BODY STRETCHES ACROSS A FIVE GALLON BUCKET HE IS IN A 30 GALLON TANK.SO I KNOW HE WON'T GET ANY BIGGER.
NO ONE HAS BEEN ABLE TO TELL ME HOW LONG THEY LIVE
HE'S ALMOST BECOME A PART OF OUR FAMILY. I'LL ACTUALLY MISS HIM WHEN HE'S GONE.