In a statement to FOX 13, ZooTampa officials said tissue and water samples were sent to different labs, including one in Germany. They said the foreign lab is "renowned as the gold standard in the water testing."
They said they also brought on two aquarium industry experts to investigate.
On May 27, all of ZooTampa’s stingrays were found dead in their 16,000-gallon touch tank habitat. Necropsies were done on all 12 rays. Preliminary results haven’t pinpointed a cause of death just yet.
"We suspect it’s water-related. Because it’s not common for all of one animal group to die all of a sudden at the same time," Dr. Cynthia Stringfield said at the time. "We always have to look at the environment, no matter what species it is."
The stingrays were housed in an area called Stingray Bay, which first opened in September 2001.