Though the average specimen in captivity might live 25 or 35 years, an old koi named Hanako, from Mino province in Japan, has been shown to be over 215 years old based on analysis of her scales, and other 100+ year old fish are known from the same pond. Koi, like wild carp, can grow to 36 or more under perfect conditions.
The gold and silver medals weigh 412 grams (0.9 pounds) and the bronze medal weighs 357 grams (0.78 pounds). They are the biggest and heaviest summer Olympic medals ever made.
The critic has made three errors in the statement of his question. When they are corrected, the problem (the perceived inability of Joseph Smith to carry the plates) disappears. Error 1 ...gold weighs 1204.7 pounds per square foot. A square foot of anything weighs nothing, for a square foot is a unit of area, which has no thickness.