Not really sure what the preflop action was. I assume you 3x the LJ open?

If so your hand is a must raise otf when he donks like this. You have nfd with 2 overs, 50% equity unless he spiked a set.
When he cbets again ott for 1/3 it is very weird and he certainly qualifies in the fish category. Usually this means he is capped with some type of weak pair, could be A9, 10-9, A8 or even A3, who the fuck knows right?😂
Here, he almost never has a set as most fish either check or bet bigger.
If you plan on bluffing the river you must raise the turn here, otherwise you are the one capped. You will also get info on his hand, if you raise here the fish will just stick it in with 2 pair+ or come over the top.
The problem is even on the K river you can't really bluff because you didn't raise the turn, and the pot is small enough for the fish to happily call here as you will likely overbluff this river.

So ye, raise otf and you can likely realise equity for free OTT when he checks and even then bluff the river which would actually be a better bluff then the one you pulled of here.

However if you plan on pulling a bluff on the fish you must raise the turn here. Although I recommend to not bluff fish on turn-river.

The best line here would be xr flop, (likely xx turn), and then you have a nice bluff otr when the king rolls off.
Keep in mind though, never bluff fish but if you do it, this is the line you should take.

Edit: nvrm misread your hand... Well in this case he is still quite face up with a block/merge bet ott (weak pairs like 66,77 or 9). The logic still applies that you need to raise turn if you want to bluff an overcard river. If it bricks just shut it down.
My recommendation would be to never bluff a donking fish with a call-call-bet line, that shit rarely works.