American tree frogs are green with a light stripe from the side of the head down the flanks. They are about 1.5 to 2.5 inches when fully grown and can be kept in a fairly small cage. Although susceptible to stress (especially from shipping), they are fairly hardy if you find a healthy frog. This species is quite readily available in the pet trade and suitable for beginning pet frog owners.
A minimum 10 gallon tank is suitable as a cage for green tree frogs, although larger is fine.
Keep in mind that frogs are arboreal and the height of the cage is more important than the floor space, so a tall tank is best. You also need a secure cover to prevent escape (mesh or wire is fine).
You can use a variety of materials for substrate such as gravel (should be smooth), cypress mulch or soil with peat/vermiculite. Just make sure the frog is not ingesting substrate while feeding. Some people use indoor/outdoor carpeting. The substrate can largely be covered with moss and cork bark.
An opportunity for climbing is very important, so provide a variety of branches and live or artificial plants. Consider philodendrons or sturdy ferns for live plants. Ensure any wood collected from the outdoors is pesticide free, and you must treat collected wood to remove harmful bacteria or bugs. Driftwood and cork bark also make good cage furnishings.
A gradient from 68-77F with a night time drop of a few degrees is sufficient for summer; provide a slightly cooler temperature gradient during the winter months.
A combination of under tank heating and/or a low wattage basking light or heat element work well; place it outside of the tank to prevent burns if the frog tried to jump on the light. Measure temperatures in various spots around the tank to provide the appropriate temperature gradient.
American green tree frogs are strictly nocturnal, so no supplemental UVA/UVB light is strictly required.
Some people believe some supplemental fluorescent UV light is beneficial, as long as it is neither too bright or used more than a few hours a day.
Green tree frogs are generally good eaters and feed exclusively on insects. Crickets can make up the bulk of the diet. They, along with other food insects, should be gut loaded (fed nutritious foods before feeding them to the frogs). For more on dealing with crickets as prey see "Raising Crickets for Food." In addition to gut loading, dust crickets with a calcium and multivitamin supplement a couple of times a week. Fruit flies, houseflies, moths and other insects can also be fed if available.
Tree frogs will likely eat more in the spring and summer months than in the winter. Feed smaller frogs daily, while larger frogs can be fed daily or every other day, using body condition as a guide. Of the frog is getting obese, cut down the feedings!
Provide a large, shallow sturdy water dish with dechlorinated water; it must be shallow since these frogs are not good swimmers. Mist the cage daily with dechlorinated water to maintain humidity. More tips on setting up an arboreal cage can be found on the Frogland site.
A Note on Extinction
Frogs can make lovely pets, but frogs in the wild are facing population declines and extinction largely as a result of human activities.
Unfortunately, the pet trade is likely contributing to the amphibian extinction crisis and the spread of an devastating infection by Chytrid fungus. For this reason, you should only buy frogs that you are sure are captive bred locally and tested to be free of disease. It may be impossible to find frogs which meet these conditions, but otherwise, pet frogs may be contributing to the decline of wild frog populations.