Elendil / Redshift wrote:"fish" is the tutorial world's id. If you have the tutorial world, it'll not work. Worlds cannot have the same id.
If you are just trying things out, you can delete the tutorial world's "Vacation.pak" file and it should work, but you'll not be able to upload a world with "fish" as an id. You can change the id in the world properties dialog (File/Properties).
I'm using the id relevant to my world--not "fish". With that in mind, can you think of another reason as to why this might be happening? Can you only travel to worlds that have been uploaded to steam?
Edit: I should mention that after paying the captain and saying goodbye, the sky picture will change to that of my world, but I will still be in Matras.