'It was a nightmare': Why you should keep your dogs away from lakes and ponds

Veterinarians are issuing a serious warning about keeping dogs away from lakes and ponds for the remainder of the summer.

The notice follows the recent sudden deaths of three healthy dogs who went swimming in Lady Bird Lake in Austin, Texas. Unfortunately for the three owners, it was an avoidable death for their pets.

Still, water can house a deadly algae growth that releases toxins during the hotter months. All three dogs were exposed to the algae when they went swimming in the lake, resulting in their sad deaths just hours later.

The blue-green algae can sicken humans, but it's rare. Veterinarian Mark Cotnam, who treated one of the dogs who died, said that the reason why dogs are so affected is that they don't know not to drink the water.

"They treated the patient as best they could, and as aggressively as possible," he told Inside Edition. "But he still expired."

While the city has started putting up signs preventing people and their pets from visiting Lady Bird Lake, vets are still warning dog owners to be wary of nearby still bodies of water. As tempting as it would be to let the dogs cool down at a lake that might look clean, it's better to avoid lakes and ponds altogether.

Vets also ask that owners make sure their dogs are on a leash. The symptoms of blue-green algae exposure — inability to stand, vomiting, and losing balance — come on very quickly, and by that time most of the damage is already done.

"I would've never gone if I knew," said one of the owners, through tears.

Watch the video above to learn more about the algae and how to keep your dog safe.