If your only on the second hand on a table and don't know your opponents.. And a fishy minbet comes out on the flop by the big blind. What do you do?

***** Hand History for Game 2956935209 *****
$25 NL Texas Hold'em - Sunday, October 30, 22:16:04 EDT 2005
Table Table 65652 (6 max) (Real Money)
Seat 5 is the button
Total number of players : 5
Seat 1: dimpoul ( $14.92 )
Seat 3: Dandy812 ( $43.45 )
Seat 4: Bob681 ( $31.50 )
Seat 5: pwd9902 ( $23.92 )
Seat 6: CavemanWins ( $24.75 )
CavemanWins posts small blind [$0.10].
dimpoul posts big blind [$0.25].
** Dealing down cards **
Dealt to CavemanWins [ Jh Ad ]
Dandy812 calls [$0.25].
Bob681 folds.
pwd9902 folds.
CavemanWins calls [$0.15].
dimpoul checks.
** Dealing Flop ** [ Kc, 5d, Qd ]
CavemanWins checks.
dimpoul bets [$0.25].
Dandy812 folds.
CavemanWins calls [$0.25].
** Dealing Turn ** [ 4c ]
kempner has joined the table.
CavemanWins checks.
dimpoul checks.
** Dealing River ** [ Kh ]
CavemanWins checks.
dimpoul bets [$0.75].
CavemanWins folds.
dimpoul does not show cards.
dimpoul wins $1.95

I figured this guy could have anything, maybe even paired the 5. I was hoping for another Ace or a possible back door flush. If I didn't improve on the turn, I was going to check/fold. Why bet into the hand to win a little or loose more. Either I hit something or fold.

Any comments?