Diseases and parasites are the major problems in the natural habitats and aquarium of pufferfish. The disease indicators of pufferfish include abnormal behavior, poor coloration, and external abnormalities. Many pufferfish species are wild-caught. In the wild, they are exposed to many parasites. The stress of the capture and subsequent transport of fish may lower the immune system of the strongest fish, making them more susceptible to the ravages of parasites. The actual diagnosis and treatment of pufferfish may become tricky. Misdiagnosis may often complicate already stressful tank conditions leading to zero effect on the disease or illness. Females have large bodies with a pair of strong claw antennae capable to attach to the gill filaments, whose locking mechanism and feeding activities damage the gill tissue of the bulls-eye pufferfish. The viral nervous necrosis or viral encephalopathy and retinopathy viruses damage the central nervous system in susceptible pufferfish species and typically affect both younger stages of fish and older, marketsized fish.