Dehiwala Zoological Garden is one of the oldest zoological gardens in Asia. It has a substantial collection of worldwide animals. It is open all year long and can be reached by public transportation. Diversity of the zoo is indicated by the presence of an aquarium, walk through aviary, reptile house, butterfly garden and many small, dilapidated cages and enclosures, housing starving, bored animals, living in prison-like conditions.
The zoological garden has a small, but picturesque butterfly garden which is decorated with small shrubs, trees, creepers and small streams. Internal temperature and humidity of the house is controlled by artificially created mist. The butterfly garden exhibits 30 species of butterflies with their all stages of life cycle for educational purposes.