Let me say from the beginning I don't care if people think this is stupid but, in a pinch when my livebearers started popping out babies I took a piece of string and strung it across the top of the tank. I hung Java Moss over it and it worked fine and it's growing kind of neat. Kind of like a Java Moss wall. Hold plenty of food as you already know.
I later added some duckweed actually the Java I think is a better cover unless the duckweed get bigger.
My own creative two cents...whatever it takes<G>