There's no clear answer in theory. You call some, you fold some.

Against a fish, I think when they check a card that makes the board heavier and then bet hard on a dry card that skews a little toward bluffs. Hands that improved on the turn are going to tend to bet the turn, and hands that didn't like the turn (eg: Ax and sets) tend to bet like giant p*ssies if and when they actually do get around to betting.

I'm a little concerned that there aren't a lot of bluffs in his range on this board but willing to take a flyer for $1.77.

It's funny that they played literally every street from the flop backwards. Take a note and move on.