nl100 underpair/3bpot vs fish

Preflop: I'll probably go for an exploitable small 3b to encourage UTG to come along. When you make it so large, the likelihood of him limp/call 3b is going to be much lower.

Postflop: I think this is a clear call down, especially against some spazzy looking fish. Expect to see him bluff with all sorts of random hands here.

I wouldn't raise the Turn btw, even though it seems that he's committted. Fishes will just bluff jam 30% pot on the River a lot unlike regs.

What size of 3bet? Is it a problem if we invite 2fish that our equity goes down a lot? I guess still not a problem.

Is co even a fish? It's still possible that he's a reg going for a smallish isoraise w a weak hand