Washington wants to get rid of the goldfish in West Medical Lake

It’s unclear how they got there.

Maybe well-meaning pet owners who wanted them gone but didn’t want to kill them. Maybe an angler who was using them for bait.

However it happened, one thing is clear: There aren’t supposed to be goldfish in West Medical Lake.

The Washington Department of Fish and Wildlife is planning to poison the lake this fall to kill the goldfish and return the lake to its glory as a haven for big and numerous rainbow and brown trout.

Goldfish may not be big but they can cause big problems. West Medical Lake is stocked with rainbow and brown trout fry each year, and WDFW officials have found that recent trout plants have been a bust largely because goldfish are outcompeting the trout fry for food.

Randy Osborne, the WDFW biologist who oversees the lake, said there are still some old and big fish left, but virtually none of the fry are living long enough to become the big trout that draw anglers there.

“What really remains in West Medical Lake is a handful of fairly large rainbows and browns, and there’s nothing coming up in the ranks to replace them,” Osborne said.

WDFW is taking public comment on its plans until July 12. The agency also held a sparsely attended public meeting on the project Wednesday in Spokane.

It’s the second time in recent memory that WDFW has tried to remove nuisance fish in the lake. The last attempt came in 2018. Osborne said anglers reported seeing the fish after that treatment, and that sampling later confirmed that goldfish were still there.

WDFW uses rotenone to treat lakes for nuisance fish. It’s an EPA-approved piscicide derived from the roots of tropical plants. The chemical kills all animals with gills, and is not known to have any detrimental effects on land animals.

Different fish species have different levels of tolerance for the chemical, and goldfish have an especially high tolerance. Osborne also said there’s plenty of places for them to hide in West Medical Lake and that it’s just tough to ensure all the fish die.

The treatment is planned for October, after the fishing season on West Medical Lake closes on Sept. 30.

If all goes well, every fish in the lake will die – including the trout – and the lake will be fishless through the winter. In the spring, WDFW will stock trout fry and catchable sizes of rainbow and browns, prior to the lake’s opening day.

There will be a lag before those fish become the trophies the lake is known for, Osborne said, but having the lake free of the domestic invaders should give the trout a good chance at growing into table fare.

He said it’s important that people know that stocking fish without a permit is illegal, and that dumping aquarium fish in a public water body can have major environmental consequences.

He said the best way for someone to dispose of an unwanted pet fish is to put it in a cooler with ice and close the lid.

Or, if they don’t want to deal with it, they can call Osborne.

“I’ll take it off their hands,” he said.