This is varicolored carp (Nishiki koi) at Dazaifu Tenmangu.
For me, the carp is a very Japanese thing.
Varicolored carps are auspiciously colored, and are loved by Japanese.
Actually the origin of carp is China, and they came to Japan in about the first century AD.
Nowadays they inhabit in all over the world.
But varicolored carp was born in Niigata Japan about 200 years ago.
Many temples have a carp pond.
When I was a child, my house had a carp pond, and my father was taking care of it.