Usually frogs can start breeding when they are 12 months of age, some species tend to take a little longer. Frogs will be activated to start breeding after a relatively dry season changes into a rainy season. In the vivarium this can be simulated by taking a period without rain first for several weeks, followed by heavy spraying at least twice a day. In my tank the frogs start calling after the 'rain' has stopped. The frogs need to be feed heavily to be in the physical condition to even think about breeding. A key rule is that the more diffrent feeding insects that you feed with the better condition will the frogs be in.
Males usually call from an elevated position and hope that they attract a female with this ritual. The higher in the vivarium the more dominant they behave. If a female fancies the idea of breeding it will follow the male through the vivarium. The male plays around with the female to verify her intentions. The male will start to call and hopes that the female will follow again, after a while the male will move to a suitable spot ( like a coconut hut or another sheltered breeding spot ). This may take an hour or even more. Sometimes it's also possible to see a female that is trying to make a male interested by touching the back of the male and trying to get the attention.
The right place or holder for the egg clutch is of course room for a lot of experience and discussion. The most commonly used place is a coconut half with an opening n front and a petridish or similar shaped article to be capable of taking out the eggs. This is most commonly called a 'cocohut'. It is recomended to add a tree leave in this dish. Some people say that Oak leaves provide the best result due to their slightly acidic nature and antiseptic properties, but I have noticed that the frogs sometimes bring in a single fresh leave before any eggs are layed. Most poison frogs don't seem to be pecific on the bowers used, it should however be a dark, moist enclosure containing a constantly moist surface but not with more than 2 mm of water under it.
The first tries are usually not fertilised or are just a gelatinous mass without eggs. The female should learn this proces and it will take some time before the eggs are laid and fertilised by the male. For frogs it is usual to use a amplexus position ( male hold the female strongly with its forelegs ) to start breeding, for poison frogs this is sometimes reported but not usual. There are also species were the male enters first and the female follows to lay her eggs in the semen wetted area. In general within the genus Dendrobatidae the male will fertilise the eggs some time after the female has already left the bower.
It sometimes happens that the animals is laying eggs and tries to fertilize the eggs but all tadpoles dies or get SLS (spindly legs syndrome). This is often a sign that the animals not are mature for breeding yet. Try to stop the breedings if possible or just let them be trying to learn on their own. Stopping breeding can sometimes be just as hard as trigger the frogs for breeding.
About the eggs
The eggs should not be disturbed for a few days after they are layed so they get some time for getting fertilized, after that period it is better to take them out of the vivarium in order to prevent other females to disturb the eggs. When there is a pair, usually the male or both attend the eggs, turns them around to give even oxygen amounts to all eggs and wets the surface of the eggs and will transport the tadpoles to a small waterbody when the eggs have come out. But this behavior is very different even within one species. It also takes time for the animals to learn the behavors. Some animals seem to never learn the behavors while some animals do their job perfect and never fails.
Most people do not take a chance and take the eggs out of the vivarium, the main reason to do this is to prevent canibalism in between the tadpoles and destruction of the eggs by rivalizing frogs. There could be benefits to leaving the eggs in the vivarium: The cocohuts could be taken and defended by the male who is trying to defend the eggs from rivalizing females. This provides some rest for the females. In captivity females are reported to lay around 2 times a month, this could cause burn out of such a female within a year. Leaving the eggs in the vivarium could be positive for the frogs, having a better productivity of frogs is another issue. For that reason the eggs are at best removed to a safe and controlled place. My personal experience is that if the parents can raise the frogs themself within the vivarium it's going to be very healthy froglets that is raised, but also more few. Mabie at most just one frog survives per clutch, but it's both interesting behavors and development that you can follow during this time if you give it both time and attention.
If you bring the eggs out it should be kept in a very humid enbironment. Usually I use a petri dish which I add a small amount if water to, not enough to cover the eggs. After a few days you should be capable to see the eggs develop. The darker spots in the eggs should remain dark for most species and finally they develop into tiny moving tadpoles. If the eggs turn white they can at best be removed, but sometimes this is not possible without destroying the eggs around. Then it's better to let it stay and hope that it wont start to mold and infects the surrounding eggs and ruins them.
Although it may seem difficult for the tadpole to come out of the egg, it is best to leave him to do his job. There are canabilistoc tadpoles and non-canabalistic tadpoles. The canabalistic tadpoles (like the tadpoles from Auratus) should be kept in seperate small containers at a temperature of around 20 - 25 degrees C. Leucomelas tads are not reported to be cannibalistic. Higher temperature might sometimes cause the spindly legs syndrome (SLS) which is characterised by the insufficient growth of the front legs and the mouth parts of the froglets. However recent literature describes that this phenomenon is more due to the physical state of the parents, possible inbreed and genetic reasons other than climate and feeding reasons. Also the how mature the adults are is making a diffrence.
Personally I prefer to keep all tadpoles separated one by one in glass canisters. Small tadpoles get small amount of water, about 0,5-1,5cm depending on the size of the tadpole. When they start to eat and grow I raise the level of the water to 4-5cm. Some people are changing water in the jars very often but personally I prefer to avoid unnecesary water changes. When you see the water getting bad it's time for waterchange and then I never change all water at one time. I always leave some of the old water otherwise it might be a chock for the tadpole. For some tadpoles I might never need to change water since they eat all food given to them and the water never gets bad. Then I just add water so to keep the level I prefer when it evaporates. Many people are using plastic polystyrene cups for one time use while I personally prefer to keep the in glass canisters from baby food.
The food used for poison dart frog tadpoles are generally based on algea. People use grinded spirulina algea with good results or plain fiskfood from the aquarium store. Small insect larvae could be interesting foodsource also. There is also a number of vitamin supplements that has been tried to prevent the SLS where usually the vitamin D3 is told to be important. The use of daylight laps over the tadpoles is another way of letting the tadpoles recieve the same effects. It's also possible to feed the tadpoles with algaes that are formed in natural light for tiny tadpoles.
After several months the tadpoles should develop hind legs first and then front legs.When the front legs develop the water level should be lowered to barely allow the tadpole to swim. The tadpole can in fact drown when the water is too high. At this moment you can stop feeding the tadpole. When the frontlegs develop the colors that the frog will get as an adult frog starts to show. At this moment I normally move the tadpole to a small box wich is a little tilted so that the waterlevel is deeper on one side and it's land on one side. The tadpole will start to absorb the tail now and it's not necesary to feed anymore. After the tail is absorbed and you see that the tiny froglet jumps around you can move it into a small vivarium where you start to feed with springtails. Be careful to not add to much food since it will stress the animals.
The small vivarium in which the froglets are transferred to should not exceed 20 litres, since they have a difficulty in finding food and it will make it easier for you to keep an eye at them. In such a small area you can keep a number of froglets, since they are peacefull but tiny creatures. Only the larger variants ( like auratus, azureus or tinctorius ) are capable of eating the small fruitflies. Most species are reliant on springtails and possibly other tiny food. The small vivarium should have plenty of food but not in such amounts that the animals get stressed by the critters. The dosing of calcium and D3 is difficult with these small food sources, creativity is required here, although after a while most froglets will eat the small fruitflies, which can be powdered better. The froglets are also poor hunters, this is another reason to fill the small tank with food.
After a few weeks of feeding and growing the froglets can be transferred to a larger enclosure for further maturing. At this point they should have started to eat fruitflies also.
Take care with the water parts so there not are any place that is deep since froglets are poor to very poor swimmers after they finally loose their tails.