As many as 100 fish were accidentally killed at Texas State Aquarium when staffers introduced chemicals into the water in an effort to control a parasite resistant to other treatments, the Los Angeles Times reported.

The rare error affected the facility's two biggest indoor tanks, noted Richard Glover, a spokesman for the facility located in Corpus Christi.

"It appears to be a truly sad fluke," Glover said. "Considerable losses were sustained."

Nurse sharks, green moray eels, spadefish, amberjack, tarpon, grouper and a sand tiger shark may all have been among the species killed; according to the aquarium's website, they were in the facility's largest tank as part of an exhibit called "Islands of Steel."

"(That) is our largest indoor exhibit, and it represents an underwater view of the habitat formed around an oil platform," an aquarium description reads, according to USA Today.

Visitors passing through Texas State Aquarium on Tuesday night found the tank's largest exhibit empty, KHOU noted. The deadly incident was met with tears from staff members, the Houston CBS affiliate added.

"Nothing like this has ever happened before," Glover said.

The medication with which staffers were trying to kill the trematoda parasite had previously been tested on a smaller exhibit and no adverse effects had been detected, the spokesman added, according to the Los Angeles Times.

"Trematoda is a class within the phylum Platyhelminthes," Glover explained. "It includes two groups of parasitic flatworms, known as flukes. They are internal parasites."

While the Texas facility would not detail the chemical in question, it insisted in a statement that the product "is commonly used by many other aquariums in treating similar issues." Perry Hampton, the vice president of animal husbandry at the Aquarium of the Pacific in Long Beach, said he sympathizes with his Texas colleagues, the Los Angeles Times noted.

"We manage health problems like parasite infections in fish and also take precautionary steps to minimize the risk to the fish, but complications can still occur," Hampton said.