Try to dive down a few feet to the bottom, the contrast in your vision will be enhanced and make the vis look even better. Try lying on the bottom and looking up as well, fish swimming above you will be even easier to see
This is a very good tip for low viz. You choose a promising spot, lay down on the bottom and look up to the surface brightened by the sky above, so that a counterlight effect will help you recognize the dark shape of fishes passing in between.
But the subsequent question is:
where to go? In facts you must know where there's more probability that some fish will be passing by. And this is THE question about spearfishing.
More specifically related to very, very, very low viz. In low viz the fish as well need some familiar point of reference, and they tend to move along a pattern given by recognizable things or objects: they will be likely to pass by rocks bigger than the average, kelp bushes, pieces of pipeline, boat docks, wrecks or any sort of familiar submerged structure. These are the best places to perform the counterlight hunting suggested by Pastor.
But this does not say it all, of course.
From what I have experienced, a fish must always have a good reason to choose a place to stay or to go to instead of another: that's related to period of the year, food chain events, weather/current events, reproduction events, type of bottom chosen by each species as a favourite habitat, and also the perception of "safety" that a fish may have in a place or another. This is so coplicated (there are so many species with different behaviour also in freshwater), and I have absolutely no experience about North-American lakes, that I quit it here and say don't ask me for specific tips.
Just ask yourself some questions: is there any species which is spawning, making eggs or breeding newborns in this period of the year? What's the depth and type of bottom chosen by that species for reproduction? That's where you have to go! It's a bit unfair and slightly cruel to shoot a fish in love or breeding, but many other antagonist species will go there looking for eggs and newborn to eat: reproduction of "enemy" species stirs up the food chain as well as current, weather and tide.
Long post! Hope it's not too boring (it was intended for newbies)