Lizard Goby

About

Found only in Japan's clear, fast-moving streams, this obscure little goby, Rhinogobius flumineus, is native to river systems stretching from Shizuoka and Toyama Prefectures westward through Honshu, Shikoku, and Kyushu. In the wild it favors the middle and upper reaches of rivers, gravitating toward open, shallow sections where current keeps the water well-oxygenated. It's a small fish, topping out somewhere between an inch and three-quarters and just under three inches, which makes it well-suited to modestly sized aquariums. One of the more interesting things about this species is its breeding behavior: males construct and actively defend a spawning nest, then stand guard over the eggs until they hatch. A level of parental investment you don't often see in small gobies. Once the fry emerge, they settle immediately to the bottom, behaving like miniature adults from day one. Rhinogobius flumineus is considered a beginner-friendly species, which is a bit unusual for stream gobies as a group. Replicating some gentle flow and providing a substrate with rocks or similar cover will go a long way toward keeping these fish comfortable and encouraging natural behaviors.