The keeping of "live" creatures has always had the potential to be heartbreaking, and many of us hobbyist have had our tragic tales of loss and failure.  Sadly this failure will set this effort to save the endangered chinook salmon back for years. 
 
About 21,000 fish, including sturgeon and endangered chinook salmon, died of chlorine exposure in a "catastrophic failure" at a UC Davis research facility, university officials said Thursday.
The loss was discovered Tuesday morning in an outdoor facility with multiple large tanks at the UC Davis Center for Aquatic Biology and Aquaculture, said Andy Fell, a university spokesperson. The facility is overseen by a professional staff, and the fish had been bred on-site.
 
https://www.yahoo.com/now/21-000-fish-die-catastrophic-030322336.html