Just a quick tip. I'd get rid of the gravel and use Eco-Earth or large river rocks. The little guys don't have a tongue they can use to push rocks out of their mouth, so if they accidently ingest a small piece of gravel, it can cause impaction and be fatal. Eco Earth will pass through their system with no problems, and large rocks, of course, they can't get in their mouth at all! Small gravel is alright in the water, as they don't eat at the bottom of the water! Just a tip to save you and your little toads problems. ;]
I have two FBT's, and I had gravel when I started too. I was told this by quite a few people, and promptly changed it.. Eco Earth is pretty cheap. Try Fostersandsmith.com. They have a three pack for like 5.99 or less... and one brick is enough for a 10g tank.
I mean, that is, if you still have them, and haven't changed up the tank at all. ;D