Florida Fish and Wildlife officials are working to figure out how thousands of fish turned up dead at Orlando's Lake Ivanhoe.

Frank Hilgenberg, who lives near the lake, reached out to us, concerned about what he saw Thursday morning.

"I could smell it when I walked around the corner, because I'm upwind, and I thought, 'Hmm,'" Hilgenberg said. "I saw guys digging around, and as I got closer I realized there's, like, eight or 10 of them, and they’re all netting out, unfortunately, the dead fish."

Officials from the city of Orlando and the Florida Fish and Wildlife Conservation Commission said they are working to determine what killed the fish.

FWC said they don’t think it’s anything toxic that’s killing fish.  They say it’s possibly something environmental that’s causing the fish to turn up dead, but at this point they don’t know for sure.

City streets and stormwater crews were called to remove the dead fish from the lake and put them in garbage bags. The water is also being tested.