Well, I'm sure if I let my water parameters get off, my frogspawn would die, but as for outside sources, this thing is invinsible!! I came home from work one day last week to find my frogspawn so closed up, you could not even see any green, and thought for sure it had died. I tested the water, and everything looked good. When I had left, it was wide open, about 4 inches in diameter, so I was perplexed. No fish, hermit, or snail had ever caused it to retreat even a slight bit, so I knew it wasn't them. I decided to just sit back and observe for a bit when I noticed towards the top of the glass something very green, like frogspawn green. A long spinned urchin I had picked up as a hitchhiker and left in the tank had plowed through my frogspawn and tore it all to pieces. Well, the urchin got his own 10 gallon tank after that, and I decided to leave the frogspawn base in to observe for a few days. Great news!! He is now back to fully opening and you could never tell it was almost destroyed!!!
10 Gallon FOWLR (and macro-algae)
20 Gallon Low-tech planted FW
30 Gallon Reef