An 82-year-old dialysis patient developed an unusual infection caused by a black mold called Arthrocladium tropicale, which had never been documented in humans before. The infection was traced to poor storage conditions and ant infestations near the patient’s dialysis supplies in Thailand during rainy season. Doctors identified the rare fungus using molecular genetic testing and treated it successfully with antifungal medication combined with removal of the dialysis catheter. This case highlights the importance of keeping dialysis equipment in clean, dry environments and preventing pest access to prevent serious infections.