Gurami (Gourami Belontiidae) and the “bolinao” (Neosthethus thessa) which is cited as found nowhere else in the world and which are among the many other existing migratory fishes (Catadramous fishes) passing through Kalinaoan River.
       The terrestrial ecosystems feature some of the rare and endangered species of palm, orchids, fire orchid (Vanda hookeriana), a relative of Waling-Waling, hardwood premium timber species like narra, molave, the Philippine Rosewood - toog, the Philippine Ironwood, Magcono, Malabayabas (Eucalyptus spp.), the marshland lotus called “pagusi’ and a local source of a delicacy nut called Nelumbo nucifera. The presence of wildlife species such as migrating birds in season that are dependent on the lake due to presence of shallow marshland and estuarine areas are observed during the first quarter of the year , including Mindanao Scoop Owls, Mindanao Savannah Night Jar, Mindanao Himalayan Swiftlets, Mindanao Forest King-fishers strong billed shrike as well as White-breasted Sea Eagle, including the common monkeys and wild pigs.

       The rich lore of Mainit points to a group of Nomadic people believed to be descendants of the Papuans as its first inhabitants. They clustered around the lake in a place traversed by Mainit River, so called because of the sulphuric hot spring called 'Mapaso" located near the river source. The Spanish conquistadores found this peaceful community here. But the constant harassment of the Moros and the "disiplinaries" forced the natives to move to a new inland site, which is the present town site. The old sit referred to "Daang Lungsod" is now the Barrio of San Isidro.

       In the 1900's when the Americans came, Mainit became a barrio of the municipality of Placer. The elections of 1928 resulted in the election of Sr. Ceferino Lozada, an adopted son of Mainit, as President with three other councilors. Together they worked and succeeded in emancipating Mainit from the mother municipality. In 1931, the municipality of Mainit was born with Antonio Mozar as its first mayor. The gold boom followed boosting the town's economy and progress. Business and trade brought people and prosperity. Mainit never had it so good.

       Then World War II came. Like other Filipinos, people fled to the mountains. Mainit had its share of the underground movement and tragedies of war, foremost of which was the death of "Father of the town" Mayor Ceferino Lozada who died in the hands of the "Colorums." These people were followers of Lt. Francisco Canuto, popularly known as "Tahid", a retired army lieutenant who succeeded in forming a colony composed of disbanded rebels with him as Chieftain and sort of deity. This colorful character also died in the hands of the Japanese.

       Liberation brought the gigantic problem of rehabilitation and the difficult task of restoring peace and order became the main job of Mayor Agapito Montaner followed by Mayor Jose Mondano. The latter who held the municipal reins for four consecutive terms paved the many improvements of the town.

       A visit to Mainit today is an excursion into the geographical, archeological and religious history. Here, the old and the new are eternally locked together.