villain is 47/16.5/4 over 140 hands. standard fish, loves to min3bet & minraise, no real history. The only hands i can see him betting this river with that i beat are random Ax hands that made 2 pair. I think he bets smaller with these hands, but i have nothing to base this on. Standard river c/f?

Full Tilt No-Limit Hold'em, $2.00 BB (6 handed) - Full-Tilt Converter Tool from FlopTurnRiver.com

saw flop

Hero (CO) ($395.75)
Button ($652.35)
SB ($194.30)
BB ($400)
UTG ($237.80)
MP ($214.85)

Preflop: Hero is CO with 5, 5
UTG calls $2, MP raises to $10, Hero calls $10, Button calls $10, 2 folds, UTG calls $8

Flop: ($43) 5, 10, 7 (4 players)
UTG checks, MP checks, Hero bets $32, Button calls $32, UTG calls $32, 1 fold

Turn: ($139) 9 (3 players)
UTG checks, Hero bets $91, Button calls $91, 1 fold

River: ($321) A (2 players)
Hero checks, Button bets $178, Hero folds