What effect(s), if any, do the tides have on freshwater fishing?

Only the mega large lakes would have tides. I’m sure the tides would help stir the pot so to speak. Maybe whatever is down deep will come up higher and get caught easier. Just a guess.

Tides in river mouths ? Don’t have much tides in lakes.

depends on species, but when water rises fish like to go near the shore for stuff that may have washed into the water, such as bugs/food.. when the outgoing tide is moving some fish like to hang out in slower areas of water, just off the running water to catch bait fish who are at the mercy of the tide and find sanctuary in these slower pools or jeddys..

The only relationship between the tide and freshwater fishing is the relationship between the tide and the moon. So basically there is no direct relation, so there is no tidal effect on freshwater fishing.

Tides will only affect coastal rivers that connect to oceans. There are no tides in any freshwater lakes that I am aware of.(Iive in the great lakes region)
The moon phases have a direct effect on spawning. (as in when)in the spring. And supposedly on fishing conditions in general.
The main reason tides affect fishing in those coastal rivers is that it will give the water more current than normal, this sets fish up to ambush prey that are going with the current. So fishing is better for that reason.