Looks to be a Dormitator maculatus.
If so, they are from the central Americas. Can accept some brackish but is OK in freshwater. They call this the Fat Sleeper.
There is also a Fat Sleeper Goby from Africa which is different but looks similar and does best in brackish.
Gorgeous fish.
I had the MEANEST Jade Goby I have ever heard of. About 8". Terrorized and eventually killed everything in my brackish tank. After killing a few new and expensive similar sized tankmakes, I ended up throwing it in with my red channa, electric cat and TSN. It kept its attitude and held its own there and escaped without a scratch when I found someone to take it off my hands.
Regardless, a gorgeous fish with a very large personality. Beautiful coloration.
Looks like you got a nice catch there...enjoy!
wow 12 inches huh? thats got some beautiful colors on it there. it gets more red and orange ashe matures. i have a jade goby at 8 1/2 inches and he barely has orange on the tips of his fins. mostly he is purpleish green stripes with the eye dot behind the gills...i dont know if you have seen a small jade goby, it looks nothing of the colors yours has. i have had mine since it was about 2 inches and it was so bland, dark greenish black with the only bright color of the eye dot wich is what atracted me to him