It is true to say that a sudden fall in temperature puts nearly all fish off their feeding. Thus when winter approaches many anglers put their rods away until the warmer months return. But most fish will start feeding again after the temperature has fallen, but far less freely than before.
Freshwater usually does not fall any where near freezing point except for the cooler upper layers where ice can often form. The critical temperature is around 39 degrees Fahrenheit or roughly 4 degrees Centigrade beneath which you will be unlikely to make a good catch as the fish will be in a state of torpor. Most of the time the water temperature will be above this and cold weather fishing can be very productive.
You should be ready to change your expectations. If you catch a handful of fish when the water is cooler this represents as successful a visit as a bag full in the summer months. When you fully accept that it is more difficult to catch when the water is colder in comparison to when it is warm you are able to enjoy some great sport.
If it is cold enough to freeze the surface of a flowing river it is easy to find a spot to fish. Areas free of ice will dictate where you fish as these will be warmer at the surface than anywhere else. You should use a fixed ledger rather than a moving bait and let the fish slowly find your offerings. Ground bait lightly as the fish will only eat sparingly and experiment with some highly flavored treats for the fish. A piece of cheese can work wonders when it is cold for the likes of roach and chub.
Because the fish only bite shyly, feeling for the takes with your fingers on the line may be your first thought. You may find it is too cold to take your gloves off to do this. Using a sensitive quill or stick float over-fished statically on the bottom can work well. If you move the bait gently a few inches every so often you will cover more ground and potentially induce a take.
You must find deeper spots in still waters that will hold warmer water than in the shallows. This might mean that you have to cast further than you would like in conditions where the fish are rather sluggish. Bread flake or crust molded onto the hook, perhaps with a smelly attractant added, works better than maggots when it is cold. If you can find very deep water say over 20 feet this will likely to be much warmer owing to the temperature gradient in such waters and the fish may be feeding very freely here. In this case large juicy worms can be a good choice where perch inhabit the water.
In conclusion, whereas the summer angler hates bright sunlight which can put fish off their feeding, the reverse applies in the colder months. On a bright sunny winter’s day the water can warm up slightly by the afternoon enough to stimulate the fish’s renewed feeding activity. It certainly will lift the angler’s spirits in the winter season!