If you must touch your toads, wear latex gloves because the oils in your skin can damage their skins. Do not add froglets to your adult toads' tank until they are of similar size -- feeding frogs will chomp anything they can fit into their mouths, including other frogs.
Fire-bellied toads will not breed without undergoing a hibernation period. These egg-layers don't get pregnant in the traditional sense -- if your toad is bloated, she is ill and requires veterinary care.
Fire-bellied toads include six species within the Bombina genus. Most are approximately 2 inches long and are green or yellowish with black spots on their backs and bright red or orange bellies. Their bright undersides warn predators that they are unpalatable, though they're typically non-poisonous and not toxic to human beings. Fire-bellied toads are active during the daytime and are fairly hardy, making them popular pets. Captive reproduction is somewhat difficult because breeding must follow a hibernation period. Fire belly toads don't become pregnant in the typical sense because these animals reproduce by laying eggs. However, it is easy to tell if your toads are laying because you'll see the eggs coming out of their bodies.
Watch your fire-bellied toads closely during the summer months. If you see one of your toads swimming on top of another, it is likely a male. However, this tells you nothing about the bottom frog -- males are extremely optimistic and will attempt to mate with virtually anything during the breeding season.
Check for eggs. Females will lay eggs as they're breeding because frogs lack penises and fertilize eggs by releasing sperm directly onto them. If you miss seeing the actual mating, you will still see eggs around the aquarium if your female is in breeding condition. Eggs may float freely in the water or be attached to plants or rocks depending on your frogs' species. Female fire-bellied toads can lay up to 200 eggs at one time.
Transfer the eggs to a separate aquarium filled with dechlorinated water if you think they may be fertile and you wish to hatch them. Use a sponge filter with very low current in your nursery tank and keep the water warm -- specific temperature varies by species, but ranges between 60 and 77 degrees Fahrenheit. Stock your nursery tank with live plants, such as elodea, to provide food and hiding places for your hatchling tadpoles.
Wait three days for the eggs to hatch. The tadpoles will live off of their yolk sacs for up to three days before switching to solid food.
Offer your tadpoles fish food for their first five weeks of life. Once they are five weeks old, you can build a section of dry land into their aquarium and add small invertebrates such as fruit flies and daphnia to their diet and increase the size of their prey as they age.