Getting all items help needed

I've managed to get most of the weapons, shields, armour, rings and helmets using big or rare prize wheels I've saved for and also bought the infinity blade. However there are still a few items in each category that I can't get. The prize wheels are just giving me things I already have now.

Are there things you can only get using the treasure maps?

I've seen the fish shaped sword as one of the items on a prize wheel but can't get it - does that mean I should keep trying for it or is it a map prize too?