Hi Trinity,
Welcome! A live plant terrarium sounds cool. If you are interested in darts, you need to do a ton of research first. Dart frog species should not be mixed, stick to a single species per enclosure. 10 gallons per frog minimum, for adults. Several morphs of darts can live in groups, but most will not do well in groups, keep it to 1:1 male:female of the same morph. 10 gallons per frog is for starters, they all do better with more space. Dart frogs get stressed easily, and that can mean death very quickly. Most prices start around $50/frog, on up, for froglets, so please don't go out and buy 20 froglets, throw them in a tank and think it will be OK. That would be like throwing $1000+ down the drain!
Dart Den has threads on building a great vivarium, so if you decide to go with darts, just look up how to build the viv. DFs love broms, and you can find all sorts of advice on other plants for vivs here too.
Temp and humidity are paramount with darts, you need to be able to assure constant temps (within 5-10 degrees) and high humidity at all times.
You will need to learn to culture live fruit flies, the mainstay food for dart frogs. They must be dusted with vitamins and minerals every feeding. They also like springtails, isopods, flour beetles, phoenix worms, calciworms, aphids, etc, but those are all optional, live fruit flies are absolutely necessary!
I believe that people who breed and keep snakes and lizards really like mixing species, making hybrids. This is absolutely NOT done with dart frogs, not by anyone who is reputable. The difference is, many dart frogs are endangered/threatened, and we need to keep the existing morphs pure. There are dozens of morphs available, and they are all beautiful--don't think we could improve them by mixing! Also if we mix the morphs, then there is more demand for catching more from the wild, thus bringing their numbers down even more. So, no mixing dart frogs!
Sorry if it looks like I am writing a book, there is tons and tons of info you need to know before you start with dart frogs! I recommend reading the various threads here on Dart Den. It took me literally months of reading up on the topic before I built my first viv, and then a few more months (for the plants to grow in) before I got my first frogs.
One more thing to keep in mind--do you think you will stay living where you are for a long time? These big tanks, full of plants, frogs, insects, etc, are NOT EASY to move. Dart frogs can live 20 years in capitivity. Tadpoles can hide in tiny spaces of bromeliads, so you can't find them easily to move them.
Good luck in your research for what kind of tank you want!
Best,
Diane
P. Terribilis orange, R. Imitator Cainarachi Valley, D. Leucomelas, D. Auratus, D. Azureus, P. vittatus, D. cobalts, D.Oyapok, Bombina Orientalis