In all, about 100 fish perished after aquarium staff administered anti-trematoda medication (exact chemical was undisclosed).  The mortalities included large sharks, morays, amberjacks, groupers, and tarpons in their largest 125,000 gallon display called “Islands of Steel” – an unique exhibit showcasing tropical sealife around the base of oil platforms (it is Texas after all).

The aquarium is now analyzing the water and performing autopsies to see what may have gone wrong.  Flukes are rather insidious parasites, and the medications to treat them can be toxic if incorrectly administered.  In other words, a lot of things could have gone wrong.

This is a good opportunity to remind all aquarists:

• Check the expiration date of any medication you plan to administer.  Chemicals have finite shelf-life.
• Read for any contraindication (interactions with other chemicals).  Some chemicals make others ineffective while others can make them much more toxic.
  
• Similarly, do not mix medications unless you know for sure they are safe to use together, and even then, try not to do this.  It’s physiologically stressful enough on a fish to be exposed to one chemical; the stress of multiple chemicals at the same time can do more harm than good.
  
• Calculate dosage … then do it again.  If you are not sure about the math, ask for help.
• In the same vein, double check your measurements and measuring tools.
• It is not advisable to treat fish in the display aquarium.  Whenever possible, treat in a dedicated hospital tank with emergency make-up water on hand.
• Quarantine is your best “medicine.”  When it comes to organisms in a closed system, there is no better truism than “an ounce of prevention is worth a pound of cure.”

Below is Texas State Aquarium’s public statement:

The Texas State Aquarium is saddened to report a loss of its indoor aquatic animal collection overnight. In an attempt to control a particularly difficult parasite that had proven resistant to other treatments, staff administered a new treatment that is commonly used by many other aquariums in treating similar issues.Many of the animals in the affected exhibits had an adverse reaction to the medication. Staff members worked diligently throughout the night to save as much of the collection as possible, but considerable losses were sustained.

Aquarium exhibits impacted include Islands of Steel, Flower Gardens, and Lionfish. Fortunately, Living Shores, Nearshore, and Floating Phantoms, as well as a number of smaller exhibits, were not affected. None of the outdoor exhibits such as Tortuga Cay, Stingray Lagoon, or Dolphin Bay were affected.

As a standard precaution, staff had tested the treatment on an individual smaller exhibit with no adverse reaction prior to administering it into the larger exhibit.

The Aquarium’s first priority is to focus on stabilizing the water in the affected exhibits. The Aquarium has sent water samples from affected exhibits to testing laboratories in hopes of a clear explanation for what caused the adverse reaction.

“This is a very sad day at the Texas State Aquarium,” remarked Aquarium Chief Marketing Officer Richard E. Glover, Jr. “We are working diligently to find out what caused the adverse reaction, and we will keep the public informed with any updates.”