The bugs in the water are not visible only because they are dead. I saw a live copepod in a cup. At first you might not notice it. However, they dart around and are extremely visible when they do so. Rashi in Pesachim says that Sheratzim are called thus because they are only visible when they move.
As to figs, I’ve been eating figs from my parents’ yard for many years and the only bugs ever noticed were ants, if the fig was cracked. We always open it regardless, just to be sure.