As we move further into spring across the Victorian High Country, water temperature is fast becoming the key factor in how the fishing plays out.

Many anglers focus on lures, baits, and locations, but one of the most reliable indicators of fish behaviour is the thermometer.

Whether you’re on Lake Eildon, Lake Nillahcootie, or working the rivers that feed them, paying attention to water temperature can turn an average trip into a successful one.

Fish are cold-blooded creatures, which means their activity levels rise and fall with the temperature of the water around them.

In early spring, cold overnight conditions can still drop the water into single digits, making the fish sluggish.

As the sun warms the surface during the day, activity picks up, especially around shallow bays and rocky points where the water heats first.

For species like yellow belly, that little rise in warmth often sparks a sudden feeding window.

Trout, on the other hand, thrive in cooler water, and the rivers running down from the alpine areas are perfect right now.

A slight bump in temperature after frosty mornings often sees them moving into faster runs chasing insects and baitfish.

Anglers drifting worms or casting small soft plastics in these runs will find fish that are actively feeding as the day brightens.

Redfin are another species highly influenced by temperature. Schools that have been hanging deep and inactive during the cooler months start to rise into mid-water levels once things warm up.

This is when trolling small diving lures or casting spinners around weed beds becomes very effective.

Cod are still a little tentative, but they too begin responding as water stabilises above 15°C, and it won’t be long before they really switch on.

It’s also worth remembering that oxygen levels in the water are tied closely to temperature.

Cooler water holds more oxygen, which trout favour, while warmer water sees native species like yellow belly and cod become more active.

By understanding this balance, anglers can plan where and when to fish.

Practical tips include carrying a cheap digital thermometer, using weather apps to predict sudden drops or rises, and adjusting retrieves to suit the fish’s mood.

Early mornings may call for slow presentations when the water is cold, while afternoons can reward a faster, more aggressive retrieve as fish fire up.

This spring, don’t just think about what lure you’re tying on — think about the water temperature.

It’s the hidden key to unlocking consistent success across our lakes and rivers.