hiya, like BuntbarschXXL says, there arent usually any ornaments or decorations, as there isnt any real need for them.
the only thing i will say, is that if you are planning on keeping the fry in their own tank, dont use gravel, if you need a covering for the floor of the tank, use aquarium sand, as this wont kill the fry when they push their way into it to hide.
as its a sad, but often forgotten thing, that guppy fry, (or any other type of livebearer fry for that matter) like to keep hidden away from the adults when theyve seen their lil brothers and sisters get eaten by mum, or other tank mates!
Hope you find this useful!
Id also reccomend reading Guppylover's post that tells you loads of things abt guppy fry, how 2 look after them, how 2 sex them, everything you need to know really!!