Last week's loss of around 400 fish at Texas State Aquarium has been blamed on the mislabelling of the chemical used to treat a parasite.
The commonly used parasite treatment, Trichlorfon, was tested before use in a small tank, which is standard aquarium procedure. There were no ill effects on the fish, so staff then treated the larger tanks with what they thought was the same chemical from a different but identically labelled container.
The treatment resulted in the die-off overnight of what is estimated to be around 13 per cent of the Aquarium's collection.
Preliminary test results have shown that the chemical used in the larger tanks was in fact hydroquinone, which is used widely in film processing and as a stabiliser in paint and motor fuels. It is also a known haematotoxic (blood poison) and carcinogenic agent.
A statement issued by the Aquarium said: "For further verification, we have also sent samples to the Texas Veterinary Diagnostic Medical Lab, and we will share additional information as it becomes available. Therefore, at this time, we are not prepared to release the name of the company from which we acquired the drug.
"We have received an outpouring of support; over 30 aquariums and zoos from all over the country, from Canada, and as far away as Singapore have reached out to offer their support and condolences for our aquarium team. Many have also offered to send us animals. In fact, the first shipment of donated fish has already arrived from the Sealife Centre in Grapevine.
"We are in the process of cleaning all of the impacted systems to remove any trace of the toxin. Once we have established the water is safe, we will begin adding new fish, which could happen as early as this week."
The loss affected the fish in several of the largest indoor exhibits, including a number of the Aquarium's iconic species such as its male sand tiger shark, Hans.
Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.
Don't forget that PFK is now available to download on the iPad/iPhone.