How to catch redfin 
Redfin are a common bycatch when fishing for golden perch because the gear is similar, as are the lures and baits used. For the best results, redfin are targeted rather than left to be an incidental catch. They are a very aggressive schooling fish and respond well to baits and lures so if one technique or location is not working, it can pay to mix things up. Once found, redfin can usually be caught in large numbers which makes them perfect for beginners and kids. Redfin habitat preferences vary. They can be found near structure such as submerged logs, rock walls and weed beds. Standing timber can also be called home, as can quite spindly and scrubby submerged bushes. Redfin will commonly swarm around the base of larger submerged standing trees in lakes. If there is no structure, then look for creek beds or bottom habitats with variation. This is where a sounder can pay dividends, including for seeing schools of redfin mid-water or finding bait balls with redfin schools nearby.
Trolling
Redfin tend to school up together and a big part of success is finding them in the first instance. That’s where trolling can be very effective because you can cover lots of water quickly. You’re also in with a chance of a golden perch or small cod.
Trolling small deep diving lures or lipless crankbaits is effective for redfin. Aim for depths of 4 to 8 metres with lures mid-water or within a metre of the bottom. Trolling two or three lines is ideal, mixing up lures until one is identified as the most productive. Lake shores with less visible timber above the water makes for easier trolling though large dead standing trees can hold fish if their branches don’t become too frustrating with snags. Once you find redfin on the troll, repeat the most productive stretches to build your catch. If only small redfin are being caught, go searching for a school of better class fish.
Boat-based lure fishing
Redfin are usually caught in lakes fishing vertically amongst submerged trees, taking up a stationary position from above and dropping baits and lures down vertically. While the vertical approach relies upon moving every 20 minutes or so, advanced sounders can spot fish at the base of trees or sitting off the main trunk and branches. Small soft plastic lures, vibes and ice jigs are effective in these situations.
Bait fishers
Bait fishing for redfin is the preferred technique for most people. Earthworms, small yabbies and freshwater shrimp all work well. When bait fishing it pays to use rigs that keep your bait anchored in the same position to avoid getting snagged too much. A running sinker or paternoster rig works well with a size #1 hook. Concentrate your efforts around standing timber and move often if you are not getting a bite. Occasionally when fishing lakes redfin are encountered in open water, well away from structure. This is where good sounders show their true worth. In rivers, it can be better to concentrate on backwaters or where the flow of the river meets a backwater.
Shore-based fishers
In lakes active fishers can walk or wade their way around with a spin rod and employ a method of cast and move. By firing a series of fanned out casts in front, then moving to the left or right to repeat, it is possible to cover considerable shoreline to intersect active redfin. This prospecting style of fishing is effective with the same lures you troll with, though soft plastics should be added to the arsenal. Choose lures that can be cast a long way into deeper water and ones that you can bounce off the bottom as they are retrieved back to shore. Longer rods will help to cast further and cover more water. Try a 7-to 7.5-ft medium actioned rod with a 2500-sized reel, 3 kg braided line and a 6ft length of 3 or 4kg leader. Bait fishers will benefit from a rod holder to anchor things down, just in case a big carp or cod take the bait.