Background Although uncommon, there is increasing interest and public health concerns of the pathogen Prototheca spp, a ubiquitous achlorophilic microalgae that can affect both humans and animals. High mortality rates have been reported in immunocompromised patients with disseminated infection, but no data is available in the immunocompetent population. Case Presentation We present the case of a 59-year-old man from rural area of Colombia who was admitted to the intensive care unit due to decompensated heart failure that was difficult to medically manage, with development of septic shock and isolation of Prototheca wickerhamii from blood culture. Fluconazole and Amphotericin B were given with successful outcome. Conclusions To date, protothecosis and its virulence factors and pathogenesis remain to be fully understood, in our case the isolation of this microalga and its implication of exacerbating chronic conditions such as heart failure is unclear. The medical-scientific community is invited to study this microorganism to determine effective management strategies, as well as its timely identification, treatment, and control, to avoid fatal outcomes.