If you grab live plants from a pet store, and give them food such as fish food (I've also heard about yeast? Idk.) they'll grow and flourish. They always seem to pop up in my breeding tanks so I never had to worry about it.
For my fry I have:
Microworms. I get a culture, and keep it going.
Decapsulated BBS: This stuff isn't live, but I shipped it in from ebay :)
Daphnia: I usually have they skulking in my breeder tank when I have live plants!
Frozen mini-bloodworms: for when they are bigger!!
Hikari first bites: to transition them into the small-adult world :)