Background. Sapphire damselfish, Pomacentrus pavo (Bloch, 1787) (family Pomacentridae) are reef fish found in tropical and temperate oceans but also are popular aquaria species in commercial and private operations; yet, there remains a paucity of information regarding diseases in this species. Thus, reporting of disease occurrences in this species is vital and serves as a foundation upon which to gather and build our knowledge base for this species. Materials and methods. Acaptive sapphire damsel presented with severe nonresolving abdominal distension. The fish was humanely euthanized and fixed tissues submitted for routine histological examination. Additionally, special histochemical stains were done including: periodic acid-Schiff′s (PAS), modified acid-fast, Pearl′s iron, and Gomori methenamine silver (GMS). Results. Grossly, a brown gelatinous material was coating the coelomic cavity and its contents, resulting in adhesion of the coelomic organs. The liver was diffusely pale. Histological examination revealed severe hepatocellular vacuolation and sheets of adipocytes replacing the hepatic parenchyma. Positive staining was observed in hepatocytes and pigmented macrophages with modified acid-fast, Pearl′s iron, and periodic acid Schiff′s. Inflammatory cell infiltrates were multifocally scattered throughout the abdominal fat and mesentery. Conclusion. The gross and histological findings were consistent with lipoid liver disease (ceroidosis), steatitis, and peritonitis. Possible contributing factors are vitamin E deficiency/depletion, rancid feed, and chronic stress. This case represents an initial documentation for this disease in this species.

fish, sapphire damsel, blue damselfish, Pomacentrus pavo, ceroidosis, lipoid liver disease, steatitis