To obtain insights into cobia cage culture in the Mekong Delta, Vietnam, 90 farmers were interviewed for technical information and fish health management practice. Results showed that the quality of artificial spawning fingerlings was unstable and become a major constraint for the development of cobia aquaculture. Most of the farmers (80%) reported having disease symptoms during cobia cultivation. The clinical signs included abnormal eyes (57.8%), parasite infection (45.6%), and ulcerated skin or external abnormality (32.2% of farmers reported). Farmers (48%) used five single antibiotics and one mixture of antibiotics to control the clinical sign by mixing with fresh water. The most common antibiotics were oxytetracycline (23.3% of farmers used), tetracycline (16.7%), and ampicillin (16.7%). Most of the farmers used chemicals following their own experience, 70% of farmers reported. None of the farmers reported being trained in the safety of handling chemicals and knowledge of chemical use. In general, there is an urgent need to train farmers on chemical use, disease diagnosis, and approach to fish health management services