Fantasy Fishing: Is the Iron-Eating Beast a Marine Creature?

In the fantasy world, there is only a little bit of land. Can't catch anything while fishing? "Ding!" "Trigger the Never Air Force skill!" "I'll hit it next time!" In this world where no one but humans can live in the water. Everything I catch is reasonable! Iron-Eating Beast→Panda Girl! Little octopus→Octopus girl! Conch→Conch girl! Blue Whale→Whale Girl! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.