$20 $40 JJ in small blind

[DeeJ]

what everyone said about 3-betting preflop.

On the turn, it looks like you're with 3 players and about 17BB in the pot. UTG looks like he's gonna call pretty much anything, probably still on a draw. Fish do win pots, and he might be bluffing. You have implied odds to draw to trip Jacks (assuming you're not dead to a straight) and you might still be ahead which I'd say about cancels the drawing dead odds. Not knowing the players at all, but against a fish I'd be loathe to fold for 1 bet.

Especially if a 6 comes on the river, counterfeits fish's 85/82/52 twopair... I can see lots of horror stories when you muck this.