Recently, various types of small gobies have been imported into the aquarium world, and they are entertaining aquarists. 
Not only do small gobies look beautiful, but they also eat the algae that grows in the aquarium, making them useful as cleaners. 
Well, its power is completely inferior to Otocinculus and Ishimakigai.

It is only in relatively recent years that the aquarium trade has begun to bring in gobies from Indonesia and elsewhere, and 20 to 30 years ago they were a difficult fish to obtain. 
Those who are interested in Japanese freshwater fish know this as a matter of course, but there are many species of this goby family, both domestically and in Okinawa. 
At a time when it was difficult to obtain overseas species, there was no choice but to enjoy raising this domestically produced species. 
The star among them is the blue-bellied goby, whose beautiful orange color and form are as attractive as those of tropical fish. 

When I was still a student, when I visited Ishigaki Island and Iriomote Island to research shrimp for my graduation thesis, wherever I looked into the river, I saw these beautiful, shimmering Gobies dancing wildly. 
Unfortunately, this phenomenon can now only be seen in some rivers on Iriomote Island. 
In areas such as Ishigaki Island, rivers have been renovated and revetment construction has been carried out, and due to environmental damage such as red soil being washed away for development, the population has drastically decreased, although they are not extinct. be.

Since his student days, he has been commuting to Ishigaki Island and Iriomote Island almost every year to photograph freshwater shrimp, which is his life's work. 
In addition to the common species, the common goby, I have occasionally seen other species that are rare in abundance, such as the black-and-white goby, the frog goby, and the black-and-white goby, but the rarest species is the hayase goby. 
I've only seen him twice in the last 30 years. 
The first time I encountered them was on a river on Iriomote Island about 20 years ago. 
At first I thought it was a blue type of Goby, but when I showed the photo to an acquaintance who knows a lot about gobies, he told me it was a rare species of Goby. 
It is true that the first dorsal fin does not extend into a sickle shape like the Chinese goby, and there are small spots on the pectoral fins. 
It can be easily distinguished from the Conteribou goby, which has a similar bluish color, by the presence or absence of spots on its pectoral fins.

Since then, I had not met them, but when I visited Iriomote Island two years ago, I was able to meet them for the first time in a while. 
The river is still a place where nature still remains, as in the olden days, with large numbers of Gobies swimming in groups, but when I looked into the water, I noticed a fish that stood out, shining in metallic blue, swimming among them. 
Seeing them meet for the first time in several years gave me a nostalgic feeling, like meeting old friends for the first time in a while. 
According to some literature, the Hayasebozu goby is said to be a species endemic to Japan. 
However, this small number of individuals is not possible for ordinary fish. 
Since this species is a bilateral migratory fish, it appears that its true habitat, with larger populations, is on other islands in the Pacific Ocean. 
It seems that there are a large number of gobies in Indonesia, such as the red goby, which is considered a rare species in Japan, which is why they are imported in bulk. 

In recent years, it has been confirmed that members of the family of gobies, which inhabit other Pacific islands, are living in Okinawa. 
Since this family of fish migrates on both sides, it is highly likely that the young fish happened to drift upstream due to ocean currents. 
It will be interesting to see whether they are migrating to extinction or whether they are starting a new distribution and expanding their habitat.