FLANDERS, NJ—A Mt. Arlington family discovered a cruel scene at Walmart Wednesday when they saw a dozen tanks without power, dirty and filled with dead fish.

Donna Lohmeyer was in the store with her 2-year-old grandson when she decided to bring him over to the live fish tanks. "It was a nightmare," she said.

And "unacceptable," according to a Walmart spokeswoman. Patch contacted Walmart's corporate office in Arkansas Thursday and was initially told the store stopped selling fish "months" ago. Photos of the tanks and their condition Wednesday that were taken by Dina Ely, Lohmeyer's daughter, were provided to corporate office for proof.

Several hours later, Walmart spokeswoman Kayla Whiting responded to Patch and said the tanks had since been cleaned. "This is unacceptable," Whiting said. "There are protocols in place that were not followed, and associates (in the pet department) will be retrained immediately."

Lohmeyer, a frequent Walmart shopper, said the tanks were without power and all filtration systems were removed. But there were still fish in those tanks.

"Most (fish) were dead, and rotting in the tanks," she said. "Many were still swimming—starving, freezing, choking on foul water full of ammonia and algae."

This wasn't a new revelation, however. Lohmeyer said other customers were in the live pet area of the store, and told her they noticed the power went off more than a week ago. The water temperature in the tanks was 64 degrees, she said.

Lohmeyer sought the store manager and was told he was unavailable and out of the building. The pet department manager was "on break" for the hour she was there, Lohmeyer said. The customer—and admitted Walmart stockholder—waited for more than an hour for an associate to come and help them.