IMO ( I raise feeder guppies) Java moss is the way to go. it spreads quickly, grows in almost any condition, and houses huge levels of infusoria which the fry can and will eat. In my Guppy tank, the fry pick at all of the plants and graze the sponges, but they really hammer the java moss constantly. They seem to like the crypt jungle for hiding in, but don't actively feed in the crypts as much. someone may argue this point, but all of my guppies seem to graze algea as well.
dave