Macropodus ocellatus is a northern fish, native to China, Japan, Korea, and Siberia. It can handle near-freezing winter conditions and thus makes an excellent subject for unheated aquariums or temperate outdoor ponds. In nature, this species is found in rice paddies, sluggish drainage ditches, and ponds; like all labyrinth fish, it is tolerant of water bodies with limited dissolved oxygen. The seasonal shift in temperatures from winter’s cold to summer’s heat is an important factor in the long-term maintenance of this fish.For breeding my Macropodus ocellatus, I found it best to condition the male and female separately in different aquariums. I did not want to risk losing my only female to an overly aggressive male, and I also wanted to time their breeding with the summer season, because I wanted to raise some of the fry outdoors. The male had been residing in an unheated, partially-filled aquarium in my bedroom throughout the winter and spring, and as temperatures rose with the summer season, I had hopes that he would soon be ready to breed.