What fish is this?

#1
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".

 
#2
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.
 
#3
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.
 
#4
Wow, that's a new one on me! Not a squaw-fish, not a pike-minnow. I don't really have a clue, but my guess would be some kinda asian milk-fish, wish you had a better picture of it.