Hi Rae, and thanks for your response.

My frogs are in a 29 gal. tall tank. I recently redid the habitat, though all the frogs..4 have been living very happily together for months. All the plants i have chosen are Frog-proof..but NO there is no real reason for pea gravel except purely aesthetic....
Through the years i have planted many terrariums and had several Viv's....some with Anoles and Newts and the Gecko or 2 (terrible hiders). Since i am a plant grower it has been fun to make them for myself and others, some for sale...Terrariums..pretty little miniature gardens..NOT to be confused i would say, after this....
The 'pea gravel' came in as an addition for looks..the Viv does have Coco fiber and small bark too, the kind you get called 'reptile bark', youve seen it.....It also has mostly sheet moss..although there is a bit of loose sphagnum that the frogs seemed to enjoy burrowing under in daytime....and of course its great for humidity....the only thing that changed from the other Viv's is the gravel and perhaps the bark is smaller....BOTH suspicious now....IN ADDITION... a few years ago my daughter had a Whites that died suddenly..and we were not in a place to really investigate why...so much was happening...it had been fine too....NO gravel...but BARK.. NOW I am reconsidering that also.
There didn't seem to be anything wrong looking about my frog today, indeed I believe I spotted it VERY soon after it died. My tank is in the living room and though I do not handle my frogs much at all, i am always misting or just watching them if I am in the room...i gave up my TV! I looked it over very well to see if there was an injury or other pathology and could find nothing to SEE. One thing for sure the gravel has got to go and I am changing the moss over to the solid type called 'frogmoss'. I USED to have that too!!
This is a hard lesson to learn! my poor Froggy! She was a beauty! stayed green ALL the time! really pretty, they all got along so well....I will be watching my frogs closely for any other problems but i think it was not a disease of any kind....she was very healthy and even appeared so after she died.
I think we can take from this that providing a HABITAT is the first order of business ....and making it a beautiful 'planting' is certainly second...
THANKS so much! this will be a really fun forum..I appreciate any help or suggestions about the necessary habitat requirements, as we remember it is FIRSTLY important..at least my little frog has led me here, maybe others will think about this danger and not make the same mistake.....for that I am grateful
I have long loved frogs like so many folks here, and my daughter has been drawn to them forever too... she is 23 now....I live on a mountain , very modestly, and am lucky have a pond out back, and I love the bullfrogs and the Spring Peepers so much..in fact after a big rain the other night one hopped right in the HOUSE !! and back to the pond it went! .....until next time... the very best to all