'Tsunami fish' story: Flooded boat. A 4,500 mile trip.

What a long, strange trip it's been for a small striped fish native to Japan that apparently hitched a cross-Pacific ride in a small boat believed to be part of a tide of debris from that country's March 2011 tsunami.

Washington state Fish and Wildlife Department biologists found five of the striped beakfish alive in a water-filled bait box on a 20-foot-long Japanese boat that washed ashore March 22 at Long Beach in southwest Washington.

Invasive species specialists also found a host of other Japanese species of sea anemones, cucumbers, scallops, crustaceans and worms living in what they call the very rare "aquarium" of water that pooled inside the upright boat.

Except for one fish that the Seaside, Ore. Aquarium has agreed to quarantine and exhibit, the rest of the critters were euthanized to minimize the risk of introducing invasive species to Washington, said biologist Allen Pleus.

The surviving beakfish goes on display this weekend at the aquarium, The Oregonian reported. Curator Keith Chandler says his staff dubbed it the "tsunami fish."

"It's pretty cool. It's about 4 inches long," Chandler told the newspaper. "We're trying to get it different things to eat ... and it may have eaten, but it's a shy little guy."

Researcher John Chapman at Oregon State University's Hatfield Marine Science Center in Newport is just back from a trip to Japan. He calls the find "stunning."

"We said this couldn't happen," he said. "And nature is like, 'oh yes it can.' "

Chapman says the fish is probably young since mature beakfish turn black. They can grow as long as 15 inches.

"There were five fish total we found in the boat's compartment, and this is the first time we've seen vertebrates come ashore in tsunami debris," Bruce Kauffman, a state Fish and Wildlife biologist in Montesano, told The Seattle Times. "Finding these fish alive was totally unexpected."

So how did the creatures survive such a trip?

The boat apparently drifted bow up, with its stern below the water's surface.

The containment area there that was open to the ocean "became a little cave of refuge," Pleus said. "The fish could go out to feed and come back in. The boat was their home, their house."

It's common for fish to associate with larger debris floating in the ocean but "nobody's seen fish that have traveled with debris this distance," Pleus said, adding, "It indicates there could be other fish floating with debris that we never see."

Most such debris gets roughed up in the surf as it nears shore, which would disperse any fish but Pleus says this boat came ashore upright.

All of which raises some troubling questions.

"There could be other types of fish associated with this debris that we don't see but down the line we could find new populations of fish established on the coast," Pleus said.

The other euthanized creatures — at least 30 different species — were preserved and sent to scientists around the country for analysis, he said.

The boat, bearing the name "Saisho-Maru," was removed from the beach.