grass carp rig`s bait`s?

Hi all
Im lucky enough to have grass carp to abot 13lb in my local canal.Ive only been able to land 1 fish of 4lb on corn at night and was wondering if anyone had any tip`s on rigs and bait`s ect.The fish can be seen during the day in the same spots in group`s of about 7-10 and i can find 3 different shoal`s on a regular basis,they are normally grouped tight together just under the water`s surface and seem to be resting.are these fish nocturnal (if not would living in a clear shallow canal turn them nocturnal?)
any advice would be great as my knowledge is only very basic on these fish (all i know is there damn hard to get on a hook and fight like banshee`s to get off again)
thanks all
alan

try popped up maize, or "zig rigs" with floaters just under the surface (birds allowing)

Try zig-rigged bread at mid water, or juust a foot off the bottom. How shallow is it?

Thanks guy`s canal is an old closed to boats overgrown type stretch depth ranges from 1 ft to 5ft but average is around 3ft and about 10ft across.
zig rig am i right in thinking its like a pop up rig with an extra long hook length or do use it like a marker float and feed out line until depth is reached?

Ive had a few grassies, all off the top, using bread or dog mixers. they dont fight too hard until they see the net then they go mental, also fight like **** on the bank.

Try to get them back in the water as quick as possible cos they're quite a fragile species!

Grass carp love particles in particular Tiger nuts and Maize. I have caught well on Trigga boilies on odd occasions but would recommend sticking to particles.
I agree with Stu regarding Grass carp which do often fight better on the bank than in the water.Large unhooking mats are essential, plus get them back asap as they are very fragile. NEVER sack them.
I would night fish over a couple of handfuls of bait on stnd hair/bolt rigs.
All the best.