How do fish feed? All fish love to eat and hate to be eaten. Therefore they're cautious when choosing a meal. Fish use their five senses to determine whether the meal is an edible friend or inedible foe. The senses used are sight, sound, feel, smell and taste. We like to group these senses into two categories, multi-direction and single-direction. For example, sound is a multi-direction sense because it can be heard from every direction, left to right, top to bottom, front to back. Smell on the other hand can be limited in that it is governed by current. If a fish is up current it will never smell your bait.
Fish feel in two ways, they feel the bait when tasting, and then there's vibration. Fish have a lateral line running horizontally along the body that enables them to feel what's happening all around them without actually touching the object causing the vibration. The sense of sight is primarily a multi-direction sense but is dependant on the placement of the eyes, field of view and a few other factors. Almost all fish can see colors in varying degrees. Water quality and the degree of sunlight can change the color of your bait. As a test, try dropping your artificial bait into a clear glass of water, hold it up to the light indoors and note how the color can change, next take the glass outdoors into the sun and it changes even more. This partly explains why one bait was productive yesterday but ineffective today.