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.
Each medal is 500 grams, and with the current market price of silver at about 63 cents per gram, and of copper at about five cents per gram, the total value of the metal in each silver medal is a little under $295. Of course, once they've been turned into Olympic medals and awarded to athletes, they can sell for quite a bit more than that.