A 15-year-old, 1.11kg, male, intact river cooter (Pseudemys concinna) presented for imbalance in the water column and systemic edema. Nonspecific abnormalities were diagnosed on hematology and biochemistry, including hypoalbuminemia and toxic change in heterophils. Echocardiography revealed pericardial effusion and pericardiocentesis. The patient was started on pimobendan, furosemide vitamin E, and ceftazidime. Despite supportive care and blood transfusion, the patient was euthanized after two weeks after intial treatment and a necropsy was performed. Multiple lesions were noted throughout the liver and PCR demonstrated the presence of Mycobacterium intracellulare. This report provided a novel technique to improve cardiac and bacterial investigation in the future.