The fish has a giant hump, but not giant size. Scaling from the size of his hand, the fish is no more than 10 inch. The OP's hand looks average, no where as big as Michael Phelps or as small as Donald Trump's.
The size and age of the OP's GT are average. Most of my male GT reached 10 inch, and lived to 5 to 8 year, by then they are vulnerable to disease or injury from tankmates. Keeping a GT solo may live longer, but I've never tried it. The OP's GT appears to die from bloat with a goldfish belly.