I know that the most popular mosses can cause impaction (Sphagnum, Frog moss, Terrarium Moss). Those are the 3 most popular sold by Zoo Med. I have tried all of those and had a scare with 2 out of the 3 and the 1 that I did not have a scare with I read impaction stories about online. Whites are very aggressive eaters and when they jump for food they will fill their mouth with the food and some stuff around it. So if a cricket can jump on it there is a chance that the frog will grab whatever the crickets on when they eat it.