Here is something to think bout: I read most of this when I was a kid and wanted to catch more Bass.
Another thing about fish, is they can see you even if you cant see them. There vision is all messed up. I read an article once about this, in darker water rivers, a bass for example can see up to 3 feet. Not in front of them, but to the sides, mostly from the top which is why they mostly attack or bite from the bottom towards the top at an angle. A northern pike can see up to 40 feet. A walleye cant see blue as well as a bass per say, catfish and bullheads are pretty much blind but a great sense of smell to locate.
This is why I believe that a light wind blowing causing little ripples on the surface, your better off fishing because it majorly refracts the light coming to this fish's eyes. So if you think you found a good spot, stay away and gently cast into it, dont make a lot of movement if you have to stand right where your fishing. Come on lets face it, our colored clothes dont even blend in with the tree and grass background, so ya, we stand out pretty bad and there checking us out and we cant even see them. LOL.
Thats why some baits, are dark in color except a few strands of bright colors, red, silver etc, or vice versa. Its is to only hold there attention while there coming up on it to inspect it, sounds and such are to bring them to the lure, lets them know something is wounded or just plain irritating to them, taste, thats fascinating, yes they can and are very fast at it, there little brains will make a split second decision to fully bite or swim off. A nibble is just them checking it out, smell and taste is at work here before they fully inhale it if it is ok. Sometimes. LOL