What size tank this is and what tank mates you have in there? The thing with these damsels are they not venture out far if you and larger aggressive fishes in this same tank. And besides all that, you just bought the fish and damsels will most the time eat right away.
Like i keep a number of damsel fishes with my eels and a good number of them find a home where they feel safe and would only venture out further if they not been feed for quite some time. This is if you have it in an aggressive tank.
Will eat Pods
as mention and flakes and most anything they can on. For that is one of the reasons, or i should say the biggest reason i have then in with my eels and they do a great clean up behind my eels.