Donald Trump showed his usual bluntness when he dumped a box of fish food into a pond of koi carp rather than sprinkle it on the water as the ritual for visiting dignitaries to Japan usually goes.

The US President committed the gaffe when prime minister Shinzo Abe invited him to take part in the act of bonding between guest and host during his trip to the Akasaka Palace in Tokyo.

The White House chief stood on a balcony above the gentle ripples on the surface when an aide for Mr Abe clapped her hands to lure the rare and colourful creatures.

And Mr Trump followed suit when Mr Abe invited him to gracefully cast over spoons of the food over the ledge - until after a few goes he looked impatient and upended the box.

His host gracefully smiled after the clumsy move during the stunt between the world leaders put on for the pack of press photographers before the pair shuffled off for important diplomatic talks.

But fish lovers gagged at the sight and wondered had Mr Trump left the koi carp - which cannot eat a large volume of food - sick or even killed them.

Twitter users lashed out after the US President dumped his box of food into the pond of koi carp in Akasaka Palace before his meeting with Mr Abe.

Lindsay Beyerstein wrote: "Trump murders beloved koi by overfeeding. It's not a Las Vegas buffet, you moron. They suffocate on the extra food!"

Sandra K Eckersley wrote: "Idiot #Trump dumps entire box of fish food in delicate Koi fish pond."

SV Taylor posted: "Oh Dear God! Everything Trump touches dies" Gonna be a slaughter of Koi fish!"

But Ruben Rosario focused on how Mr Trump had potentially damaged this symbolic act with Mr Abe.

He posted: "Do I have to explain how F**ked up what TRUMP did to the KOI Fish IS? The KOI Fish Ceremony dates back to the days of Buddha an is Considered a source of Good Luck. To rush this is Highly Disrespectful."

A website for fish experts and lovers - Aquascape - gives advice warning owners of koi carp not to give them too much food.

It read: "Overfeeding occurs anytime the fish are eating more than they need. This can make your fish sick."

Mr Trump jetted into Japan during his 13-day diplomatic trek through Asia. He will next head to Korea, Vietnam and the Philippines during his five-nation tour of the region.