Bombina orientalis is one of 6 members of the genus Bombina. It spends most of the time floating or swimming in ponds and streams. It's green or brown with black spots and patches, except for the ventral region which is red and black. One major problem is distinguishing males from females.
Males generally have rougher backs and their forearms are thicker than the females.
These minor differences make them almost identical except during the breeding season, when males have black horny nuptial pads on their fingers and forearms. One way of telling which frogs are male and which are female is to observe the behaviour of the frogs. Whenever a frog tries to jump on the back of another frog and use the arms to grasp it, it's definitely a male. If the male isn't rejected immediately, there is a good chance that the second frog is a female and that she is even prepared to breed. If the frogs haven't yet reached sexual maturity, there's no easy way to make sure that you have got both males and females.