Every year we spot a frog in the small pond in our garden. This pool frog is the smallest of three species of green frogs that are found in the Benelux (pool- or small green frog, bastard- or middle green frog and lake- or large green frog). It has a grass-green to brownish colored back, often with a slight longitudinal stripe and sometimes with dark spots. Its white belly is only faintly mottled and males have white croak-bladders. It has relatively short hind legs and can grow to a maximum of 7 cm in size, but usually the length fluctuates between 4.5 and 5.5 cm.