Coccidiosis in an aquarium-managed common octopus ( <i>Octopus vulgaris</i> ): classical macroscopic and histologic features.

Coccidiosis is the most prevalent disease in octopuses under human care; however, detailed macroscopic and histological examinations illustrating its hallmark features are scarce. This report presents a classic case of severe coccidiosis in an aquarium-derived formalin-fixed common octopus ( Octopus vulgaris ) as an educational resource for veterinarians working in aquatic medicine.