playing OOP, rivered flush

PokerStars No-Limit Hold'em, $0.25 BB (6 handed) Poker-Stars Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver Cards)

SB ($24.75)
Hero ($24.55)
UTG ($10.20)
MP ($5)
CO ($15)
Button ($19.80)

Preflop: Hero is BB with , . CO posts a blind of $0.25.
UTG calls $0.25, 1 fold, CO (poster) checks, 1 fold, SB completes, Hero checks.

Flop: ($1) , , (4 players)
SB checks, Hero checks, UTG bets $0.75, CO calls $0.75, SB folds, Hero calls $0.75.

Turn: ($3.25) (3 players)
Hero checks, UTG bets $1.5, CO calls $1.50, Hero calls $1.50.

River: ($7.75) (3 players)
Hero checks, UTG bets $2.5, CO raises to $5, Hero folds, UTG raises to $7.7, CO calls $2.70.

Final Pot: $23.15

Yes, I actually missed this flush, but when I saw the showdown I started to wonder exactly what would be able to pay me if I had hit it.

I didn't actually need to get paid much. I got 3.3:1 on the flop and 4.2:1 on the turn. If my flush was good, a small v-bet would be enough to turn a profit. On the other hand, a pretty big part of my opponent's ranges were also fds, some better than mine, some worse. If I lead the river it's likely that a weaker flush will just call and a stronger one will raise, so I lose value there. Even given the odds, is this a muck on the flop?

i bet out with pair + FD, c/r non nut flush draw and c/c with nut FD.