I snagged its thick spiney rearward dorsal fin at lake herman vallejo yesterday. Its bronze with white underside. Small mouth and head like a mullet, no teeth, big belly, pretty strong. Its probably a huge "Hardhead" native California fish. Its almost 4lbs, about 16".
IMO it looks like a squawfish, or pike minnow. If it is, it is non-native and they like to eat salmon spawn so F&G wants them removed. I catch plenty of these (although much smaller) for bait in Suisun.
Based on head and jaw morphology it looks like a Sacramento blackfish (Orthodon microlepidotus). Pikeminnows have larger lips, proportionally larger mouths, higher-set eyes, and a more compressed head and body shape. It is a California native, as are both Sacramento and Colorado pikeminnows, despite the bounties placed on them.