I've been keeping leopard frogs for about 2 years now and recently had one of them die. I found it in the tank fully extended and in full rigor mortis. It looked it it had just passed (was actually hopping around just an hour ago). On exam, I felt an abdominal mass and when I opened him up I found him to be fully impacted with stool that largely consisted of sphagnum moss substrate; interestingly enough there was no rectal prolapse. I'm guessing he died from an impaction. While I do know other things can cause fecal impaction (ileus from overwhelming infection, parasites), I wanted to know what substrates would be better tolerated by frogs/less likely to cause impaction. Thanks.