Researchers have identified columnaris-causing Flavobacterium bacteria in Brazil for the first time, including species previously found only in Asia and the United States. Published on August 4, 2026, the study revealed these nearly transparent, fish-killing pathogens in regions such as São Paulo, Minas Gerais, and Paraná, affecting both Nile tilapia and native Brazilian species like tambaqui, pacu, and Amazon spotted catfish. The researchers emphasize that rising water temperatures and biofilm formation significantly favor the growth, persistence, and spread of these pathogens in aquaculture facilities. Because traditional visual identification under a microscope can easily miss transparent bacterial colonies, the findings highlight an urgent need for enhanced disease surveillance and specialized hygiene protocols. Laboratory tests demonstrated that species like Flavobacterium davisii and Flavobacterium indicum thrive at optimal temperatures close to normal Brazilian inland waters, with Flavobacterium indicum peaking at 35 degrees Celsius. Furthermore, the ability of these bacteria to form protective biofilms allows them to survive on farming equipment, tanks, and nets between disease outbreaks. To combat these threats effectively, scientists recommend implementing strict equipment disinfection procedures and developing autogenous bath vaccines tailored to specific strains. Utilizing weakened bacteria in immersion treatments offers a practical way to protect young fingerlings whose immune systems are still developing without requiring individual injections.
