I got a fuzzy fwarf eating after a few weeks im sure a zebra would be similar.
Unfortunately you may need live food to start with SW shrimps are the best thing as guppies are pretty rubbish nutrition wise. Every few days try dead shrimp/prawn or whitebait ect. After a few weeks it will start recognizing whatever you drop in as food. It just takes awhile. I have easy access to small shrimp for free at the beach 2 mins away so was easy for me but way be abit harder for you if you cant get live shrimp.