Enables palmitoyl-CoA 9-desaturase activity and stearoyl-CoA 9-desaturase activity. Acts upstream of or within monounsaturated fatty acid biosynthetic process. Located in endoplasmic reticulum. Is expressed in several structures, including alimentary system; central nervous system; genitourinary system; respiratory system; and sensory organ. Orthologous to human SCD (stearoyl-CoA desaturase). [provided by Alliance of Genome Resources, Apr 2022]