Villain is some form of fish, 38/0 over 15 hands so far.

The turn barrel may not be good, but I was thinking (even based on the limited sample) that he could fold quite a lot of weak pairs that he stationed the flop with like 88-99 and Tx stuff, and could call with diamond draws, QJ, AJ, AQ that sort of thing.

On the river, if he checks, I'm obviously just checking it back and getting to showdown - he's never folding any king.

The donk is wierd though. I think he'd bet smaller with a good king, and he'd probably have raised the turn with a set. The board is wet enough that he can have a lot of bluffs here, and this is a typical fish bluff line. The only bluffs I'm worried about are Tx, and I imagine he quite often thinks it is good and tries to get to showdown anyway.

Do you station this, or do you think it's a fold?

Poker Stars, $0.05/$0.10 No Limit Hold'em Cash, 6 Players
Poker Tools Powered By Holdem Manager - The Ultimate Poker Software Suite.

BTN: $14.18 (141.8 bb)
SB: $4.55 (45.5 bb)
BB: $18.24 (182.4 bb)
UTG: $7.22 (72.2 bb)
MP: $10.91 (109.1 bb)
Hero (CO): $10 (100 bb)

Preflop: Hero is CO with 7 7
UTG calls $0.10, MP folds, Hero raises to $0.50, 3 folds, UTG calls $0.40

Flop: ($1.15) 5 K T (2 players)
UTG checks, Hero bets $0.50, UTG calls $0.50

Turn: ($2.15) 4 (2 players)
UTG checks, Hero bets $1, UTG calls $1

River: ($4.15) 2 (2 players)
UTG bets $5.22 and is all-in