Japanese Garden koi fish

The koi fish collection at Cal State Long Beach's Earl Burns Miller Japanese Garden is being replaced after a virus recently killed off the garden's entire koi population.

Approximately 300 koi were killed by the koi herpesvirus (KHV). The fish contracted the virus between October and January.

KHV is a pathogen that affects koi and common carp. It cannot be transmitted to humans, nor can it be cured. According to the garden's director, Jeanette Schelin, garden employees were unaware of the virus during the first half of that period, she said.

Employees noticed symptoms of an often-deadly gill fluke parasite in some fish prior to the garden's annual koi auction in October. The fish were given treatments and the garden did not auction off its infected koi, Schelin said.

At the auction, adult koi were auctioned off for $50 to $300 each. Schelin estimated the total value of the deceased koi population to be no more than $30,000.

"There's just no good way to put a value on it," Schelin said.

The fish were expected to improve within a few weeks after the auction, but "they were still dying," Schelin said.

"It wasn't consistent with a parasitic outbreak," she said, noting that the garden treats koi for parasites every year. "It's kind of like treating your cat or your dog for fleas," Schelin said. "It happens."

Some koi were then sent to the Aquarium of the Pacific in Long Beach for tests before being sent to UC Davis. Although the koi did have the gill fluke parasite, they also had KHV, Schelin said.

"That was very bad news for us because the koi herpesvirus is a very deadly virus," Schelin said. "It usually has a 100 percent mortality [rate]."

By mid-January, the garden had lost all of its koi.

To make sure the pathogens did not get into any other body of water, garden employees were told by UC Davis to disinfect the fish and dispose of them in plastic bags.

The ages of the koi ranged from young fish of 7 to 8 months, to adults that have been at the garden for years. According to Schelin, it is not uncommon for the garden's koi to live for 20 to 30 years.

"The biggest concern is how do you stop another outbreak of this," Schelin said. "How do you get this disease out of the pond?"

This is made harder by the fact that the source of KHV in the pond has not yet been determined.

According to Schelin, there are three possible explanations.

One is that birds could have carried the virus while traveling from pond to pond. Another is that someone could have secretly thrown their own koi into the pond, infecting the others. People often purchase koi and later realize they are unable to take care of them, Schelin said.

The most likely explanation for the disease infestation, according to Schelin, could be due to fish that are donated to the garden. When the garden receives these donated fish employees keep them separated from the other fish for 30 days, monitoring them to make sure the fish are healthy before introducing them to the rest of the koi population.

The pond was drained and sterilized and, in the future, the garden may implement a testing procedure to check the koi.

In order to harvest a new koi population, approximately 200 baby koi were purchased two weeks ago, each about 6 inches in length. According to Schelin, they were bought at a discounted price for about $1,000 through UC Davis and a Northern California company. According to Schelin, UC Davis uses the company as a test site, which certifies that the koi are disease-free.

The garden has also ordered a batch of 100 "juvenile" fish, which are considered "teenagers" and are 10 to 14 inches long. This batch will cost around $7,000, Schelin said.

"We never know until we actually get the bill," she said.

The garden will receive a total of 30 boxes of fish, shipped as if they are "'FedExed' from Japan to the United States," Schelin said.

"It was pretty exciting to open up those boxes," Schelin said of the first batch of replacement koi to arrive at the garden.

Due to budget constraints, the garden will not buy adult fish, which typically cost $500 to thousands of dollars each, Schelin said. She said it takes five to seven years for koi to mature, which accounts for the higher price of the older koi.

"Keeping koi is labor intensive," Schelin said. "You can't ignore them for even a day."

The koi are being purchased using money from the garden's emergency "rainy day funds," Schelin said. Members of the Friends of the Japanese Garden program, who each pay a fee for joining, also hold fundraisers and donate money.

The Earl Burns Miller Japanese Garden is currently accepting donations. According to Schelin, they have raised about $1,000 so far for the koi.

"They are a symbol of our garden," Schelin said. "They add so much color and beauty to the garden."

She said thousands of people visit the garden a week, making the koi sociable.