Gostaria de saber se essa história é Boa Montanha como sua other question .
Não é um mundo totalmente aquático, mas existem cidades flutuantes, as Novas Ilhas, e elas recuperam metal de ossos de peixes. O mar é rico em ferro e as criaturas do mar concentram ferro em sua carne e ossos:
World’s Edge: In some past eon, the city stood on the Continent’s shoreline, nothing beyond but darkening skies and bottomless water. For generations, this great port had served as a home for fishermen, and more importantly, for the brave souls who journeyed onto the trackless sea-hunting giant rust-fins and the copper eels and vicious many-mouths. Fortunes were made from every carcass brought home—great masses of inedible meat and iron-rich bone pushed into furnaces and burned away, leaving nothing behind but a few dozen kilos of precious metal.
As ilhas não têm tanques de hidrogênio abaixo deles, mas eles têm tanques de metano:
With the best alloys in the world, insulated tanks were built, and they were filled with methane and dangled far beneath each Isle, using the sea’s own pressure and cold to help keep the gas liquefied.