Famous for his Guinness World Record-setting discovery of the world's largest freshwater fish, Bleher carried out freshwater and brackish water research in hundreds of countries and established a scientific publication titled Aqua: International Journal of Ichthyology.
He spent his childhood accompanying his mother on aquatic research missions to locales such as Equatorial Guinea and Brazil. He later relocated to the United States and studied at the University of South Florida.
In the late 1970s, he established an organization called Ornamental Fish International.
He was one of four children born to Amanda Flora Hilda Kiel and Ludwig Bleher. His maternal grandfather, Adolf Kiel, was an aquatic plants and animals researcher who, in the early 1900s, founded the largest fish farm in the world.
He is a contemporary of Swedish biologist Svante Paabo.