Enables cholesterol O-acyltransferase activity. Predicted to be involved in cholesterol efflux and cholesterol metabolic process. Predicted to be located in endoplasmic reticulum and membrane. Predicted to be active in endoplasmic reticulum membrane. Is expressed in several structures, including hatching gland; liver; pleuroperitoneal region; retina; and yolk syncytial layer. Human ortholog(s) of this gene implicated in coronary artery disease and hepatocellular carcinoma. Orthologous to human SOAT2 (sterol O-acyltransferase 2).