A new pygmy seahorse that's roughly the size of a grain of rice and looks as if it is 'wearing paisley' has been discovered in southeastern Japan.

Dubbed 'Japan pig', the miniature creature measures just 15 millimetres in length and lives inside seaweed, soft coral and algae reefs.

Researchers have described the newly-discovered animal, whose Latin name is Hippocampus japapigu, as looking like a normal seahorse dressed up in paisley.

Japan pig is one of only seven known species of pygmy seahorses.

Scroll down for video

A new pygmy seahorse called 'Japan pig', that is the size of a grain of rice, has been discovered in southeastern Japan. The male (left) is 15.59 and the female (right) is 14.54 mm in size. They hide in seaweed to avoid predators

Although smaller seahorses have been spotted by divers for years, it wasn't until scientists studied the 'Japan pig' they realised it had never been described before.

The vibrant marine creature was found around 178 miles (287 kilometres) south of Tokyo at Hachijo-jima Island by researchers at the California Academy of Sciences.

'Japan pigs' are found in soft coral and algae reefs, between five to 22 metres (16 feet to 70 feet) beneath the surface.

'It's like a seahorse wearing a paisley pattern,' Kevin Conway, associate professor and curator of fishes at Texas A&M University described to National Geographic.

The Japan pig is one of around seven known species of pygmy seahorses.

It is not essentially rare, but its size makes the species difficult to spot, scientists say.

Unlike larger seahorses, the pygmy species have not been caught up in the trade for traditional Chinese medicine or aquariums.

Most pygmy species have two wing-like structures on their back but the Japan pig only has one.

Researchers led by Graham Short from the California Academy of Sciences note that they are active and playful creatures that survive on a diet of plankton.

'Japan is recognised as a global hotspot of marine biodiversity, with 53 recorded species of syngnathids, including ten species of seahorses of which four are true pygmy seahorses,' researchers wrote in their paper published in ZooKeys.

'The new species can be further differentiated by... a striking reticulated white and brown lattice pattern on the head, trunk, and tail.'

It is the fifth species of pygmy seahorse recorded in Japan.

Three specimens were collected with hand nets by scuba diving and external morphological characters were documented using a dissecting microscope.

The female on the left is 16.33 mm (left), and the specimen on the right is a mere 15.59 mm long male. The Japan pig is one of around seven known species of pygmy seahorses

This is the fifth species of pygmy seahorse recorded in Japan. Three specimens were collected with hand nets by scuba diving and external morphological characters were documented using a dissecting microscope

The vibrant creature was found around 287 kilometres (178 miles) south of Tokyo at Hachijo-jima Island by researchers at Texas A&M University

'Fundamental information on the taxonomy, systematics, and distribution of pygmy seahorses is still relatively sparse in comparison to the larger seahorse species,' researchers wrote.

The first species of pygmy seahorse was described in 1970, while other species have been discovered since 2000.

'Most are known from very few specimens and only three species have been analysed genetically,' researchers said.

Six pygmy seahorse species have been documented throughout the central Indo-Pacific, from the Coral Triangle, West Pacific, Australia, to central Japan.

Seahorses are renowned for being poor swimmers, with some of the smaller species only able to reach speeds around five feet an hour.

But the seahorse is the equivalent of a stealth fighter jet – it's head and body is shaped so that it causes minimum disruption as it moves through water.