How Water Temperature and Clarity Change Where Fish Sit

Weather gets the blame and credit, but water is what fish actually live in. Temperature and clarity are the two measurements worth paying attention to, because both change behaviour directly.

Temperature sets the pace

Every species has a preferred range. Outside it, fish eat less, move less and hold in more comfortable water. That means temperature is usually a question of depth and location rather than technique.

• Cold water: fish group tightly, feed rarely and prefer slow presentations and smaller meals. Find the deepest, most stable water available.
• Warming water: fish move shallower, toward cover and sunlit banks, and feed more aggressively.
• Very warm water: fish seek shade, deeper water or moving water, often feeding at night or at first light.

A thermometer reading, not an air temperature, tells you which of those situations you are in.

Clarity sets how far a fish will travel

In clear water fish can see a lure from a distance, which makes them easier to spook and harder to fool. In stained water they rely more on vibration and silhouette.

• Clear: use natural colours, lighter line, longer casts and quieter presentations.
• Stained: use brighter or darker colours, rattles and vibration, and fish closer to cover.
• Muddy: fish tight to structure and use baits that push water.

Fronts and light

A passing cold front often pushes fish deeper and tighter to cover for a day or two, and the fishing usually improves again as conditions stabilise. Low light periods concentrate feeding activity because fish are more comfortable moving shallow.

One variable at a time

Before changing lures, ask two questions: is the water warming or cooling, and is it clearer or dirtier than last trip? Adjust depth for temperature and presentation for clarity, and you will usually be closer to the fish than a lure change would put you.