I'm thinking of trying for perch and roach in a pretty deep (15 to 20 feet) canal dock. I've got a 9 foot 6-weight rod and a floating line. I'm thinking of starting in the middle of January. I guess I'd need to get down deeper with an intermediate or sinker though?

Does anyone have any advice or can anyone point me towards some advice? I come from a river trout background so I'm not too confident here.

I guess fry patterns for perch and buzzers and nymphs for roach?

Don't be afraid to throw in some chopped up worms first, to get them in an area you can then try to tempt them with a fly. Otherwise, fishing blind, you could be in the wrong spot, wrong depth.

Black and red with silver. (So something like a bloody butcher in colouration)
Red with white.
Red worm patterns, like a blood worm marabou. Weighted to get it down.

I've had some success with a gold head coral fritz in deep water, especially if there are a few fry about...............birdsnest

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Fear not if I steal from your side, as of yore, from paradise streams to fish Teifi once more.
BN based in Wolverhampton

Don't be afraid to go pretty big for perch. If they are there they will take it. I often take them when fishing for pike with flies 5"+ long (and if you do use anything that looks like a 'predator fly' - use a metal trace of 10" in case one of the crocs hits it).

Ask the coarse anglers where they have been catching perch. As tailing loop says, wrong spot - no fish. All but the largest perch will shoal up with fish of a similar weight to themselves for the winter, so if you find one, there will be more.

They will be following the shoals of silver fish, so if you do find the perch, you will most likely have found the roach.

Re: the roach, I have never specifically targetted them in a canal - but your choice of nymphs/buzzers are definitely where I would start!

Let us know how you get on.

N

If it's anything like the canals I fish, then cast parallel to the bank to start with. Perch like structures. I've found corrugated metal retaining walls hold a lot of fish on my local waters. It always pays to cast along/towards these structures.

Finding a shoal of Perch is key. Once you've found them then you will catch on any fly that has a bit of flash in it. Don't be afraid to use a large fly either.

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If you're a defender and he heads it that low you take his head off, it's as simple as that. - Roy Keane

Some great advice here, guys, thanks.

Unfortunately the only others who fish there are cormorants, and they're really tight with information.
Still, I do see them coming up with roach a lot so there must be a good few roach in there.

Could I cast a wire trace with a 6 weight?

haha

Wire trace on a 6 weight, just depends how heavy the trace and fly setup you use is. Authanic wire with a small connecting ring/small swivel may just be OK. You'd be better off with a #7 or #8 weight, but if you need, give it a go.

Test out some smaller perch type flies on a mono leader, like small zonkers, about size 6-8 long shank. Black, red, silver, holographic, flashy. If you find yourself getting hit by pike, it's time to tackle up a bit.

simonb is spot on with feature finding - any tree roots coming into the water, debri in flat water spots or man made structures will attract fish.

Finally, perch take flies a bit differently to other species. They have such a big mouth that they tend to 'suck in' the fly (creates a mini negative vacuum when they open up their mouth behind a fly). If you can see them take a fly in clear water, you'll see what I mean. If you do find yourself with a deeper hooked perch, be very careful unhooking, as their vital organs are very close to their potential 'hook-hold zone'.

N

If you want a fine wire trace for Perch that will give you some protection against pike then try this.

AFW Surflon Micro Ultra - 6.6lb Camo - AFW - Trace Wire

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If you're a defender and he heads it that low you take his head off, it's as simple as that. - Roy Keane

i wouldnt bother with wire if you are only using small barbless hooks say 10,12+. perch fishing with lures can be a struggle in the middle of winter,location is key.

This year I fished a deep river lock on the fly and on one session I caught more than a friend who was using maggots.
We decided to have a friendly competition, to be honest I thought he would win hands down using bait, I would of been happy to catch one perch.
Twenty minutes later he had caught one perch and I had caught five.....
We both could not believe this so we had a look at what was happening in the clear water.
His maggots were being ignored as they drifted down past the perch one or two would swim up and investigate but would then turn away. The maggot eventually drifted to the bottom and stayed there untouched.
We then watched the fly, I cast in a small gold bead ptn then watched it sink down deep to perches level. I could see the gold bead under the water glinting in the sun. A perch moved forward to investigate then backed off slightly. Just as it was about to turn away I twitched and jigged the fly upwards using the rod tip, the perches gills flared and it lunged at the fly.
The perch wanted a moving bait they could not resist a possible meal being snatched away and on this day this is what they wanted. Most of the perch I catch have been caught this way, the clearer the water the better your chances are if you can see there reaction to the fly.
If you can flyfish for trout then you can catch perch they love chasing a fly and can hit it hard at times. I would avoid using a wire trace unless you were using large fry patterns. Small nymphs will catch roach as well as perch. Wooley b....rs and dog nobblers also work really well. Fish close to cover and keep the fly moving!