Blackfin dartfish

The back half of the body is black.

Scientific name	Pterelrotris evides
English name	Blackfin dartfish
Japanese name	Kuroyurihaze
Classification	Actinopterygii
Classification details	Perciformes Ptereleotridae
Full length	~10cm.
Distribution	Indo-Pacific. South of Chiba Prefecture.

Characteristics

The back half of the adult fish's body is black. They swim with their dorsal and anal fins spread out. The head is a bright yellow or light blue color. Total length is about 10 cm.

When they are juvenile, their body is transparent and the black of their dorsal fin is also pale.

Ecology

They live on reefs and coral reefs. They sometimes hover in the middle layer without touching the seabed.

Habitat

Miura Peninsula, Arasaki

I photographed a school of juvenile fish swimming in the middle layer of the rocks at Arasaki. There were about 10 of them floating between the surface and the reefs. Since it was still a juvenile, its color was pale, but its dorsal and anal fins were fully extended.