My opponent is fishy, about 35% V$IP (GTW+ rocks, by the way).

Party Poker No-Limit Hold'em, $ BB (9 handed)

SB ($24.65)
BB ($36)
UTG ($25)
UTG+1 ($26.87)
MP1 ($47.37)
Hero ($23.75)
MP3 ($25.25)
CO ($3.5)
Button ($23.75)

Preflop: Hero is MP2 with , . SB posts a blind of $0.25. CO posts a blind of $0.75.
2 folds, MP1 calls $0.50, Hero raises to $3, 5 folds, MP1 calls $2.50.

Flop: ($7.50) , , (2 players)

OK, the hand converter doesn't seem to be handling this properly, so:
MP1 bets $3, Hero raises to $9, MP1 raises to $27, Hero calls $11.75 [all-in].

Is 3-1 good enough to call someone fishy here?

I think you have at least 6 outs if you're beat which I would say just about swings the call here. It's close though. I reckon you're paying about 25% of the pot, if he has two pair you win nearly 40% of the time, making it an easy call, if he has a set you win about 23% of the time. You're blatantly dead to a straight but holding two of the queens that holding seems mighty unlikely. If he has the fishy AJ you are, of course, creaming him. With that combination of possible hands I think you have over 25% of the equity in this pot so a call is fair enough.

Monk
xxxxx

Hmm, didn't realize it was so high against two pair, which is what I was most worried about. In that case, it's an easy call.

He did in fact show down the fishy AJ. Afterwards he said something like "I hate top pair ace kicker."

If our stacks were deeper, this would have been a much tougher call.