Tragedy struck at the Harvey Mudd College koi pond earlier this month when excessive amounts of chlorine killed all seven fish.
A failed valve, which facilities and maintenance staff noticed Nov. 2, “introduced an excessive amount of fresh water to the pond, which contain[ed] more chlorine than the fish can handle,” according to an email to the HMC community from Theresa Lauer, senior director for facilities, emergency preparedness and safety.
HMC officials did not say when exactly they died.
“Seven koi were impacted and seven koi have been replaced,” Lauer said in an email to TSL.
No fish can survive at chlorine levels above 0.35 mg/L according to Pond Place of Michigan. Unfiltered Claremont water contains nearly five times that level, with an average level of 1.8 mg/L of chlorine, according to the Golden State Water Company 2019 Consumer Confidence Report.
To prevent future koi deaths, facilities and maintenance staff have added a safety measure to the replacement valve that will “help mitigate the valve from being in an open position for an extended period of time,” Lauer said.
In addition, she said, all the valves in the pond have been placed on a “preventative maintenance program” that will identify ahead of time when a valve requires replacement.
“We really enjoy the koi and were devastated by this turn of events,” Lauer added.
At least one of HMC’s koi has been killed by chlorine before, between 1980 and 1988, former President D. Kenneth Baker wrote in a history of the college.
“It was removed from the fountain and placed in the college swimming pool,” he said.
Mudders have long been fond of the fish, which reside in Hixon Court outside the entrance to Galileo Hall.
“When I was a [first-year], I would come out of the dark, drab lecture hall after CS5 … lecture to spend a little time in the sunlight and say hi to the koi,” Briana Liu HM ’19 wrote in a blog post last year. “The fish aren’t exactly affectionate, but they do swim to the side of the fountain when you walk up.”
This article was last updated Nov. 22, 2019 at 12:50 a.m.
This article was updated Nov. 21, 2019 at 9:04 p.m.