The idea that a century-old eel could grow to monster proportions seems nice, but it is completely without scientific background. I once wrote an article about this for a magazine, based on the growth-rates of many hundred european eels which were examined for a scientific study in Ireland. It came out that even the very largest eels were still well lesser than 1,5 m, and some of them were over 60 years old. The growth becomes slower and slower the older the eels become (as in nearly all other animals which can grow during their whole life). Even if an eel would live for 200 years, it would not grow bigger than 2 m, because its growth would have slowed down to nearly zero. The very largest documented eels were around 1,5 m, what fits perfectly with the dates of maximum size for a very fast-growing and very old eel.
