Cownose stingrays (Rhinoptera bonasus) kept under managed care breed commonly, although cases of dystocia and pyometra have been reported previously. Feti are typically implanted in the left uterine horn and only the left ovary is functional. Cesarian section has been reported but carries risks of hemorrhage and recurrence of dystocia in multi-sex exhibits. An adult cownose ray, kept in a public Aquarium, was presented for severe coelomic distension and anorexia. On coelomic ultrasound, a dead fetus surrounded by hyperechoic heterogenous fluid in the uterine lumen was visualized. Due to the suspicion of pyometra, a left hysterectomy was performed under anesthesia using propofol, tricaine methanesulfonate and an antinociceptive combination of butorphanol 0.4 mg/kg, lidocaine 6 mg/kg, and robenacoxib 2 mg/kg IM. The initial goal was to perform a bilateral ovariohysterectomy, but due to anesthetic complications, the procedure was stopped after left hysterectomy, visualization of a normal left ovary and coelomic lavage with Elasmobranch ringer lactate. The ray recovered uneventfully. After incision of the uterus, a mummified fetus surrounded by pus was visualized. Uterine culture yield Acinetobacter johnsonii and Staphylococcus epidermidis. Antibiotics prescribed for 5 weeks included florfenicol 30 mg/kg IM q3 days followed by trimethoprim-sulfamethoxazole 30 mg/kg q48h PO based on sensitivity results. Appetite resumed within a week after surgery and no complication occurred post-operatively. On re-evaluation, coelomic distension resolved progressively, no signs of coelomitis, ovarian disease or gestation were detected using ultrasound, complete blood count and coelomic fluid analysis. The ray is doing well 2.5 years after undergoing this procedure.