Boleophthalmus pectinirostris

B. pectinirostris (Mutsugoro in Japanese) is distributed in Japan, Taiwan and southern China. This species is an important part of the fisheries resources in these countries. It is difficult to cultivate this mudskipper, although techniques for breeding B. pectinirostris are under development.
The skin is smooth, with many conspicuous cobalt spots on the body and fins.
B. pectinirostris has a slender body and very large dorsal fins with many cobalt spots, differing from B. boddarti which is distributed in southeast Asia.

Their chins are flat, enabling them to graze easily on the algae and diatoms at the surface of the mud.

There are some notches in the lower jaw. The algae grazed by the mudskipper easily goes to the mouth through these notches.

The lower jaw with notch is very rough to the touch.

Many tracks are observed around the nest. The tracks are made while the mudskipper moves to forage and aggressively defends its territory.
Adults of both male and female B. pectinitrostris each have their own nest. They often enter their nests to repair.

The 12th - 14th of July 2003 was the midst of the breeding season in the Shiranui estuary of southern Japan.

I observed the courtship behavior of B. pectinirostris, where each mature male competed for the acquisition of females.

Courting display starts from a dynamic jump of the males. They jump up while spreading all their fins to appeal themselves to the females. This is 'the load of tideland'.

The power for the dynamic jump comes from kicking the caudal fin. Then, the instantaneous power breaks!

However, after a magnificent jump, they flops its whole body like a fretful child. It is funny.
It is possible to distinguish sexes in B. pectinirostoris.
In the males, 3 spinous rays of the first dorsal fin are elongated.
In the females, only one spinous ray of the first dorsal fin is elongated.