i want to try this and want to try it on the river nene (northampton england)
i live here it

i normaly go course fishing there

there's
roach
minnow
crewfish

and i dont know what else could i have some information / pic of flys to use (not good with name of fly im just a new starter)

The Nene has many species, Roach, Bream, Chub, Pike etc.

What is a Crewfish?

Due to the depth of the river I suspect some sort of weighted nymph may be an idea.

Craig,
Two catchable coarse species to target with a fly rod on this river would be chub and pike. Firstly the chub. A good all round outfit would be a 9ft 5wt medium action rod coupled with a weight forward floating line and if possible a spare reel spool with a weight forward intermediate line on it. Use a tapered leader down to about a four pound tippet. On the floating line flies such as a size 16 flashback pheasant tail nymph fished under a size 12 olive klinkhammer duo style (do a search on here for it) or wet flies such as a peter ross or bloody butcher (fry imitations) have done well for me in the past as have gold head hares ear nymphs. Dry flies work well, especially sedge flies or daddies skated across the surface. On the intermediate you could do worse than an olive and white minkie. This is a really good fry imitation and is a large mouthful for a hungry chub, perch or pike. Retrieved in a stop start, jerky type motion a minkie works well for me. Another good tactic with a minkie if you can see the chub and sight fish to them is to have it on a very short line and slap the lure into the water a foot in front of the fish. A chub will rspond to this as if a food item has fallen into the water from trees or bushes and can nail the lure really hard. The trick to this is not to alert the fish to your presence, if you do it is game over and the chub will disappear. There is a theory that a chub once disturbed will take one hour per pound of body weight to come back on the feed. Chub love cover, especially over thier heads so a good place to look for them is overhanging trees, weed rafts, fallen trees in the river etc. Smooth glides at the tail of weir pools can be good for chub, especially on the dry fly. If there is a match or coarse angler around, they may be able to point you in the right direction. Be stealthy, keep your eyes open (polaroid glasses help) and don`t ignore the bank at your feet, especially if it is undercut.

A good all round pike outfit imho would be a 9ft 9wt rod with a middle to tip action coupled with a large arbour reel carrying again a floating and intermediate pike taper line. These are designed purposely to cast large wind resistant flies. You can buy purpose built pike leaders but whatever you use, you must use a bite proof trace on your tippet. There are many opinions on the best type of trace material to use, but a good quality, soft wire of around 30lb breaking strain has never let me down. Do not be tempted to fish straight nylon as you would for trout. A pike will bite straight through this and it is unfair to leave hooks in a fish. Despite their fearsome appearence pike are a delicate fish to handle on the bank and do not do well with being dropped or kept out of the water too long. An unhooking mat is a good thing to have to lay the fish on whilst it is being unhooked. Two basics for unhooking here are a baker hook out (google it) or strong long forceps and a filleting glove. The safest way to unhook your pike is to lay it on it`s back on the unhooking mat and kneel astride the fish. Slide the middle finger of the hand wearing the filleting glove into the gill cover carefully and follow the line of the jaw towards the front of the fish. You will find the pikes bottom jaw opens easily and you can retrieve the fly with the forceps or hook out. Carefully support the fish with both hands and cradle it gently in the margins until it gains the strength to swim away. You will need a good strong net for pike too, not one with micro mesh as a pike can spin in the mesh and if you have any flying hooks these become tangled in the mesh and the fish becomes stuck (the mclean salmon weigh net is good but expensive). The best advice I can give you is if you have not fished for pike before or are afraid of them, go with an experienced pike angler the first few times and learn the basics.

Flies for pike are not flies at all but lures designed to imitate small fish and swimming rodents or amphibians. Fished around likely ambush points such as lily beds, stream mouths, dam walls or shoals of prey fish should produce a few strikes. Also look for scattering fry or small fish. This can give away the presence of trout, perch, chub or pike.

The rods, reels, lines, traces, unhooking tools and flies are available from lots of tackle shops these days, do an internet search but a few I would reccomend are Sportfish (www.sportfish.co.uk), and Andy Lushes shop in Tunbridge Wells (www.thefriendlyfisherman.co.uk ). There are good flies available on here www.ukswff.co.uk, Foxons are a brilliant tackle shop (www.foxons.co.uk) and have a good selection of second hand rods and of course there are loads of good fly tiers on the forum who may tie you some for the right price.

Hope this helps you Craig and if I can help any more, drop me a pm,
Good fishing,
Andy

__________________
The trout in yonder wimpling burn
That glides, a silver dart,
And, safe beneath the shady thorn,
Defies the anglers art

R.Burns

crewfish are like lobsters i catch them on sweetcorn there fun things all u got to do is drop a hook with sweetcorn on few weights a small float and put it in the bank close in and wait for the float to go if u want come to northampton and ill show you :P

I think you mean the Signal Crayfish which obviously has no place being discussed on a fly fishing forum and being a non native species shouldn't be in the river in the first place but thats annother issue.