"I eat fish all the days." Although awkward in English, shouldn't this be accepted as a literally accurate translation?
Yes, "i eat fish all days" is totally correct
"All days" is unnatural in this context.
could you also say "cada dia"?
hmmm... without a context it's not frequently used: "Como peixe cada dia da semana"
Todos dias means each day? I thought todos means and dias is plural meaning days?