Huge Fish
I would expect his flop calling range is super wide, and will pick up gut shots on the turn that he will call a turn bet to. By the river his range is still so super wide its pretty sick. Equity is still over 65% (*non*Educated Guess) Stove it up with 65% of hands, and start deleting them one by one. Lots of combos of T's, but lots of other garbage too.

Don't confuse your calling range on the flop or turn with villains calling range.

IP Bet an amount that Fish can still call with his wide range. Basically PP,6,4,2, Ax.
I don't know what bet size is optimal, but should be targeted so he calls the river with these weak hands.

OOP I like to know if a fish will bet if checked to. I always want to know how aggressive a fish is on the river, because I will let him decide what amount he is willing to call (bet). On this board they will even bet their air (pot size), putting you on two high cards that can't call. A random six will seem like the nuts to a fish on the river if it's checked to him.

Check calling is also good against a random river raise when he has any PP that waited until the river to raise. (I think usually this is a turn raise for a fish though) Nothing is worse then planning a bet/fold when villain finally raises river with KK-77.