Like most dart frog dads, your male leucomelas most likely transported the tadpole to the body of water via piggyback. If you choose to leave the other tads in the enclosure he will most likely do the same for them. Since dart frogs do not lay their eggs in water, tadpoles have actually survived for up to a week riding around on dads back without being deposited into water. If you do leave them in the vivarium, be mindful of water quality! The water needs to be kept very clean to successfully raise the tads into froglets. Also keep in mind that a lot of the dendrobatidae species are cannibalistic as tadpoles, so don't be surprised if the larger tadpoles make the most of their weaker siblings! Check out Saurian.net for some good ideas on raising tadpoles and dietary needs. The information that Patrick gives is really good. I would also check out tincs.com, their care pages are very thorough, and they even give step by step instruction on care through out the tadpoles development.
Brent
Congrats on the tads! I have had my leucomelas for about 8 months now, but no eggs yet. :x
The male leuc must have transported it to the water dish, as for the others, I'd take them out and raise them yourself, or add more water dishes to your vivarium for additional deposition sites.
hock: