Straight on turn faced with river push on flush card

[ATM]

I wasnt sure what i could beat here that moves in on river. Villain was a bit of an idiot but not completely foolish and only hand i thought he could push with on the river was a flush. Is this fold to nittish? Comments appreciated on all streets.

pokerstars 6 max $0.05/$0.10

BB = $5.60
SB = $19.65 (Hero)
BTN = $11.70
CO = $4.30
UTG+1 = $10.40
UTG = $4.80 (Villain)

Hero is dealt 6[img]/images/graemlins/heart.gif[/img] 7[img]/images/graemlins/heart.gif[/img]

UTG calls $0.10, UTG+1 folds, CO calls, BTN calls, Hero calls, BB checks.

Flop ($0.50): 4[img]/images/graemlins/club.gif[/img] 5[img]/images/graemlins/spade.gif[/img] 9[img]/images/graemlins/diamond.gif[/img]
Hero checks, BB checks, UTG checks, CO checks, BTN checks.

Turn ($0.50): 8[img]/images/graemlins/spade.gif[/img]
Hero bets $0.50, BB folds, UTG calls, CO folds, BTN folds.

River ($1.50): 4[img]/images/graemlins/spade.gif[/img]
Hero bets $0.70, UTG raises all in, Hero folds.