Do I have to call the river?

Just another fisherman catching one on me, or should I know to fold this to a river value bet? My only read is the opponent likes to slow play monster hands.

PokerStars: Hold'em No Limit ($0.10/$0.25)
Table 'Rana' Seat #6 is the button
Seat 1: captn bukfst ($41.15 in chips)
Seat 2: Shazmeister ($7.95 in chips)
Seat 3: Stretch69 ($9.25 in chips)
Seat 4: SillyString ($25.55 in chips)
Seat 5: IckeyMouse ($24.65 in chips)
Seat 6: luckyspirit ($53.10 in chips)
Seat 7: me_pud ($12.85 in chips)
Seat 8: GTBobby ($8.90 in chips)
Seat 9: Osterskog ($21.60 in chips)
me_pud: posts small blind $0.10
GTBobby: posts big blind $0.25
*** HOLE CARDS ***
Dealt to SillyString Q J
Osterskog: calls $0.25
captn bukfst: calls $0.25
Shazmeister: calls $0.25
Stretch69: folds
SillyString: calls $0.25
IckeyMouse: folds
luckyspirit: calls $0.25
me_pud: calls $0.15
GTBobby: checks
*** FLOP *** J 4 J
me_pud: checks
GTBobby: checks
Osterskog: checks
captn bukfst: checks
Shazmeister: checks
SillyString: bets $1.75
luckyspirit: folds
me_pud: folds
GTBobby: folds
Osterskog: folds
captn bukfst: calls $1.75
Shazmeister: folds
*** TURN *** J 4 J 6
captn bukfst: checks
SillyString: bets $4
captn bukfst: calls $4
*** RIVER *** J 4 J 6 5
captn bukfst: bets $6
SillyString: calls $6
*** SHOW DOWN ***
captn bukfst: shows A 9 (a flush, Ace high)
SillyString: mucks hand
captn bukfst collected $24.05 from pot

Maybe bet more on the turn. Looks like he was calling you anyway. Rather stupid call by him on a paired board. Just a fish drawing out on you. Pretty easy crying call on the river too. Nothing wrong with your play really.

Bet the turn more for sure. Make him pay for his last spade if he's really fishy enough to go for it. $6 on the river was a decent value bet by the opp, not really worth calling if it were any more.