Tucson Parks and Recreation personnel determined what appeared to be a fish kill in the pond the weekend of June 10, according to a statement from Paul Cunningham’s Ward 2 Office.

The dead fish were removed from the pond and the turtles were moved to Silverbell Park. A limnologist, a person that specializes in fresh-water systems, was brought in to look at the oxygen levels in the pond.

The surface oxygen was determined to be safe, but Tucson Parks and Recreation personnel will continue monitoring the pond. It’s suspected the issue is caused by toxins generated from algae in the pond.

The plan for Parks personnel is to drain and seal the pond to reduce long-term effects. The pond will remain fenced off to prevent harming other animals.