TAMPA (WFLA) – Officials with ZooTampa at Lowry Park are investigating after 12 of its stingrays died this week.

The zoo announced the deaths on Facebook Thursday night.

“It’s with heavy hearts we share that today ZooTampa lost 12 residents of Stingray Bay,” the post said.

According to the post, the zoo’s animal care and veterinary teams are examining all of the mechanical equipment involved to figure out what happened. They’re also testing the water in Stingray Bay. So far, the zoo says all indicates “optimal water quality and conditions.”

Zoo officials say it may take several weeks for all of the test results to come in. They also noted that Stingray Bay is a closed system that only houses rays.

“Please keep our team in your thoughts – every professional here loves the animals we care for, and any loss is a difficult one,” the Facebook post said. “Thank you for your support.”

Stingray Bay will remain closed for now.