Courtesy of the ABC

Meteorologists in Japan are puzzled by a recent series of downpours - not heavy rain, but fish and tadpoles falling from the sky.

Japan may be deep in recession and facing a crucial election, and just over the horizon North Korea may be threatening to fire a missile overhead, but animals raining from the heavens is headline news.

It all started in Ishikawa prefecture on the country's west coast when residents began to notice strange creatures lying dead in their gardens, on roads and in car parks.

"I found a dozen small fish on the footpath near my house," one man said.

"I have no idea how they got here. At first I thought it was some sort of prank."

Then about 100 tadpoles were found in the council car park.

"I found these tadpoles," a woman said. "They must have rained down overnight.

"I'm astonished because tadpoles don't fly."

Soon reports began flooding in about similar fishy downpours all the way from Hiroshima in the south-west to Iwate in the north-east.

One theory speculated that the creatures were sucked up by mini tornados or waterspouts and then deposited in towns and villages.

But meteorologist Mamoro Akita quickly put paid to that hypothesis.

"The weather radar hasn't picked up any rains or tornados in the affected areas," Mr Akita said.

"So it's unlikely that tornados or waterspouts have been sucking up fish and tadpoles and raining them down."

Whatever is causing this biblical-type rain, it's powerful. One man reported finding more than a dozen small carp plastered on and around his truck.

Another theory suggests large birds such as herons or gulls have been dropping the fish and tadpoles mid-flight.

"It's possible these creatures were dropped by birds which scooped them up as prey," wildlife expert Tetsu Hayashi said.

"Maybe they dropped them when disturbed during flight."

Japan is in the middle of its annual rainy season, but this mystery of the fish and frogs falling from the sky is a long way from being solved.