$5 NLHE 6-max: K5 vs river pot donk

25/0/25hands
most of the draws missed, is it a standard calldown on the river?

IPoker, $0.02/$0.05 No Limit Hold'em Cash, 6 Players
Poker Tools Powered By Holdem Manager - The Ultimate Poker Software Suite.

Hero (BB): $6.81 (136.2 bb)
UTG: $5.09 (101.8 bb)
MP: $1.19 (23.8 bb)
CO: $5 (100 bb)
BTN: $5 (100 bb)
SB: $6.07 (121.4 bb)

Preflop: Hero is BB with 5 K
4 folds, SB completes, Hero raises to $0.15, SB calls $0.10

Flop: ($0.30) 5 6 8 (2 players)
SB checks, Hero bets $0.20, SB calls $0.20

Turn: ($0.70) 5 (2 players)
SB checks, Hero bets $0.50, SB calls $0.50

River: ($1.70) J (2 players)
SB bets $1.70, Hero calls $1.70

I check back the flop personally.

As played I think it's a fold. He can have full houses, straights and flushes. It's rather rare that a fish is willing to put all his money in by himself without you doing the betting for him.

Although I did say he is a fish, he isn't one in the conventional sense. He is more tight/passive. Which if anything makes it less likely he makes a move here because he has a narrower, more value-oriented range.

call

definitely check back flop , you had bottom pair

i think u played the hand perfectly ... why wd he check back, hes got to make the cont.bet

With K5o, I only want to see the flop. After flop I can bet or see free card. Better for me is free card, because your opponent can have pocket pair and have a set. It is classic war BB vs SB, everything is possible. If I see free turn in this board I wait on his move. Maybe he again makes a check, slow play something, then with three of a kind I prefer bet. On the river - call for me. In my case pot shouldn't be so big.