Preliminary test results returned to the Texas State Aquarium Tuesday and point to a mislabeled container that may be to blame for the deaths of hundreds of the Aquarium's fish last week.

It was a major loss for the Aquarium. It happened last week when staff were treating the tank system for a parasite using a chemical they believed to be trichlorfon. They later discovered that it had an adverse effect on the animals, killing a total of 389 fish, including sharks.

In all, about 14-percent of the animals housed at the Texas State Aquarium were killed. Staff there are now in the process of cleaning all of the impacted tanks to remove any trace of the toxin.

During a news conference Tuesday, Aquarium CEO Tom Schmid said preliminary test results showed that it was not trichlorfon that was used, but a totally different chemical that never should have been shipped to the Aquarium in the first place. He said the container was mislabeled.

"The preliminary results indicate that it was absolutely not that chemical, so somehow during the potentially manufacturing process, or some point in time, that container of medicine was incorrectly mislabeled," Schmid said. "We know that was not trichlorfon. Leads us to conclude that was the cause for the mortality event."

There is now an investigation into how the wrong chemical arrived at the Aquarium. The actual product used was an isomer of hydroquinine, which is a known blood poison.

Hydroquinine is an industrial chemical that is used in things like film processing and as a stabilizer in paint, motor fuels and cosmetics. Officials at the Texas State Aquarium said they have sent more samples to a lab for further verification.

The Aquarium has received overwhelming support and donations from the community. They are hoping once the water is safe that they will be adding a new fish tank system, which could be happening by the end of the week.