Fifteen bonnethead sharks died overnight and were found in their tank at the Indianapolis Zoo Tuesday, according to TheIndyChannel.com.
An excess of ozone in the tank caused the deaths, according to zoo veterinarians. Ozone is used to dissolve organic waste in the tank.
The excess occurred after an ozone-regulating system in the tank was taken offline for maintenance; the zoo is now reviewing the tank system and repair procedures, zoo spokeswoman Judy Gagen said in the article.
The zoo is looking to replace the bonnetheads, a small and common variety of hammerhead sharks native to the western Atlantic and eastern Pacific oceans, she said in the article.
-C.R.
