Thanks all I think I'll try using the same kind of mesh I have over the tank I have my African Butterfly Fish in. Although I have that under a lid for extra security during feeding time and plant rearrangement, I can make the mesh pretty tight and it should be good enough for the frogs. The lucky bamboo's pretty used to being pressed against and tied together for shaping, so I can make the mesh snug around the top of the plant and keep an eye on the little guys. If I notice any funny business I'll go and buy a new lid since mine has a gap for the filter anyway - more than a 1 inch gap
Thanks for the advice guys! Although I only ordered 1 frog, I received 2 and they're just cute as can be I remember always begging my mom for a little frog when we'd go to a store called Zainy Brainy - store full of educational toys and stuff for kids including a shelf of ADFs in 1 gallon tanks - and she'd always say no! So about 10+ years later I've got a couple little dream frogs in my tank