Its a plainfin midshipman. I've seen a few caught on plastics and bait but you might be the first on a fly. Are congratulations in order? They're called toad fish on the east coast because of the sounds they make. Their sounds were a big mystery in San Fransisco bay for years. If you've ever been diving while the males were doing their "singing" you'll never forget it. Mike
http://www.dosits.org/audio/fishes/plainfinmidshipman/