transmigrate into a merman in apocalypse world

a university student passed through into an apocalypse world packed with zombies, mutated creatures, aliens, and many more .but who would've thought that he not only has to deal with this world horrors but he also has to accept that his current body is useless. mc: what can I do when I'm a mermaid now ?!! the sea is full of mutated monsters, the land is also full of many more !!! thank goodness I had my golden finger or I'll die of hunger ...............huh?!! someone is falling from the bridge, let's go save him!!