Hi Lisa Marie ! That is a very nice looking enclosure. Some FBTs tend to be greenish while others are brownish. Also there are bluish morphs too. They also can change from brown to green depending on environment and even stress.

IRT coloring food; I've read that to get the red belly, you have to feed tadpoles with a high carotene diet. Still; have not read anything about the green color associated with any foods.