Yes it's brackish. Aquarium care would probably be virtually identical to that of the violet goby. Soft substrate, something to hide under, frozen or small live foods like worms. They're smaller than violet gobies, and more elongated but they still get about a foot long so a tank around 75 gal would probably be good.
BTW, if you're able to find someone in America selling them (I've been looking for a good year or so) please tell me.