Contrary to what you will read in most "care sheets", unmilled moss is not safe to use as a substrate for your frogs. Not only does it greatly increase your frogs risk of impaction (far more than any coco substrate), but it is a breeding ground for bacteria. The small amount of coco ingested when a frog eats a cricket is nothing compared to strands of moss that wrap around and constrict intestines or ball up in the gut (if you watch, they usually get most of it out). The green moss has been dyed, which is not safe, and either type will not only grow bacteria, but attract gnats (fruit flies, no-see-ums, whatever you want to call them), not to mention the fact that crickets and any other live prey you will provide will immediately hide, which will annoy you and encourage your frog to grab a mouthful of moss. Bed a Beast, Eco Earth, or any other coco substrate is recommended, and can be mixed with milled (ground up) peat/sphagnum moss for texture, moisture retention, etc. Even potting soil can be used, provided that it has no fertilizers, pesticides, and other additives. However it works much better as a substrate when mixed with the coconut husk substrate. Orchid bark of course provides a great risk, as do some other soil substrates marketed towards "tropical" vivariums. Jungle Mix and now Forest Floor, for instance, many times includes large slivers of wood that pose both an impaction and external injury risk. All substrates should be given a good once over to check for large pieces, and moss should be avoided.
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*~~Whitney~~*
Though here at journey's end I lie in darkness buried deep, beyond all towers strong and high, beyond all mountains steep, above all shadows rides the Sun and Stars forever dwell: I will not say the Day is done, nor bid the Stars farewell."