The toad inhabits zones of steppe, forest steppe, broad-leaved and mixed forests consisting of different species of trees. In the forest steppe and steppe zones, B. bombina inhabits bushlands, forests and wetlands in floodplains, covered with dense vegetation. It inhabits also open landscapes, using drainage channels as pathways for dispersal. At the southeastern margin of its range, the species lives in permanent freshwater bodies in river valleys surrounded by an arid saline landscape. It is primarily an aquatic animal living in shallow stagnant lakes, ponds, swamps, peatbogs, ditches, flooded rice fields and quarries. Sometimes the toad inhabits semi-flowing waters: springs, irrigation channels, rivers and stream pools. In some areas, however, it seems to live almost entirely in stagnant water bodies. As a rule, the water must be clear. In the Carpathian region, B. bombina lives in wetlands with clearer water than the congeneric B. variegata. However, near the southern margin of the range, in Southeastern Ukraine and Krasnodar Region of Russia, the toad often occurs in chemically polluted waters: settling and sedimentation reservoirs, rice fields, polluted ponds in settlements and cities etc.

• Terrestrial
• Freshwater

The toads prefer relatively warm conditions: they are active at +10 - +30oC, usually +18 - +20oC. Active individuals are found in the daytime, but the maximum calling by males occurs at dusk, whereas during windy or cold weather toad activity decreases. Fire-Bellied Toads stay in the water or near the shore; terrestrial migrations occur mainly at high air humidity, as a rule at night. Hibernation occurs from the end of September or October (sometimes the beginning of November) to late March or April. The toad hibernates in the mud on the bottom of water bodies or on land. The breeding season extends from May to the end of summer. During this time, male vocalizes floating on the water surface, with body flattened. Sometimes he is able to call from under the water. Amplexus is pelvic. The clutch contains 80-300 eggs, sometimes more, deposited in portions. Embryonic and larval development takes 2-2.5 months. Metamorphosis extends from the second half of June to the end of September. As a rule, it peaks in July-August. Recently metamorphosed toadlets stay in the water and near the shore. Sexual maturity is attained in the 2nd-4th year of life, longevity in nature reaches at least 12 years.

Tadpoles consume mainly algae and higher plants, lower animals frequently are eaten. Newly metamorphosed toadlets prey mainly on insects (Coleoptera, Hymenoptera, Diptera), adults consume mainly various insects. More than half of their diet of adults may consist of aquatic invertebrates, but terrestrial animals are also numerous. Variation in the proportion of aquatic prey in different samples reflects the extent of terrestrialism the toad in different landscapes and seasons. During the breeding season, feeding is not stopped.

When faced with a potential predator, B. bombina exhibits a defensive posture called the unkenreflex. It turns over and curves its bright belly upward, covering the eyes with its palms. Otherwise, it may not turn over but instead curve its body downward, lift up the head, and curve the extremities showing the bright spots on its flanks and on the ventral surface of the extremities. Despite the venomous skin secretions in the Fire-Bellied Toad, many vertebrates regularly consume its adults and juveniles. For example, its proportion in the diet of Nycticorax nycticorax in Ukraine may reach 25%.