I got this species under the name Rhinogobius brunneus lindbergi from a German hobbyist who has been keeping and breeding it for over 10 years now.
I’m rather unsure about the actual species determination, as the taxonomy of the genus Rhinogobius is quite confusing. Most obviously the species belongs to the R. brunneus-complex, which is widespread in China, Taiwan and Japan. The actual R. brunneus doesn’t occur in Taiwan, though. I was told that the ancestors of my specimens were most likely imported from Taiwan – if this is the case, they would probably be correctly identified as R. candidianus.
Whatever you call it, this species is quite beautiful in its on way. It may not have the most vivid coloration, but still has some highlights like the male’s elongated first dorsal fin and a facial expression that can only be described as cute. It also has some interesting feeding preferences; while it rejects most dry and pellet foods, it can be fed all kinds of live and frozen foods. I noticed that even if I don’t offer any of these for a while, the Rhinogobius stayed in perfect shape and always seemed to have full bellies. It took me a while to figure out the reason for this: They feed on algae (the green, hairy type) as well, and actually seem to perfectly get by on this diet over a longer period; they just don’t really get into breeding shape without the addition of live food. Another excellent and easily available food source I have recently found to be dried Gammarus – scuds, the type you can buy for freshwater turtles. Dried scuds float on the water surface, though, that’s why they weren’t intended for my Rhinogobius in the first place. But again, these gobies surprised me: After a few weeks of quietly observing other fishes doing this, they had learned to take the Gammarus from the surface. For some reason, only the females do this; the males are either not clever enough or just too relaxed to lift their bodies all the way up from the ground…
Talking about breeding, this species is said to produce rather large eggs with larvae hatching relatively well-developed. Mine already showed some courtship behaviour (on which I made some interesting observations I’m going to tell you about somewhen) and probably already spawned at least once, but I was not able to spot, let alone separate and rear any larvae yet. I’ll keep you updated on this.