Fire bellies are very simple to keep. A land & water set up is best. No special heating is required, room temp is fine. A lot of times you see them in a pet store in an aquarium with almost all water & maybe a little haul out. If you notice, they don't have much color to them, mostly all black. I have one in a mixed terrarium with more land than water & mine stays a bright green. I've had him about a year & he has never turned black. He spends about 1/2 of his time in the water. I was once told that they only turn bright green during mating season, must be all year long at my house, lol. I was also told that he might be staying that color because I have a uvb bulb on him even though it's not required.
One thing that is very important with these little guys is that you change the water every day if you use a water bowl for soaking like I do.
They are pretty big eaters for being little guys. They scarf down crix like no tomorrow, along with any other insect you put in front of them.
Hope this helps. If you have any other questions, let me know.
Oh yeah, I forgot to mention....even though they aren't tree frogs, they still like to climb. Keep a top on the tank. They also like to burrow. They're kind of like an all around frog/toad.