Crews at the Feather River Hatchery said they need to shut down to do maintenance on water pipes.
Starting June 30, no guests will be allowed to visit for two months while crews do that maintenance work.
All of the fish that are more than a year old will be released back into the Feather River and the others will be taken somewhere else to continue breeding.
"This is the second time this has happened in the last 40 years so normally we have fish here, but this year we transferred our fish to our Thermalito Annex facility,” said Feather River Hatchery manager, Anna Kastner. “This will give them a chance to do the major maintenance on the line."
The hatchery will be transporting more than 450,000 fish to the Thermalito facility off Highway 99. They are slated to reopen on September 15.