At what size or age do cc spawn .and about what water temperature.

3 lbs is lower weight and middle 70's F is where spawning starts. Better minimum weight is 5 lbs.

Is there a chance of smaller ones having a limited spawn say 1.5 to 2 pounds .just trying to figure out if I need to remove the smaller ones and move some larger ones from my other pond .they are between 12 and 18 pounds.

Smaller ones will spawn if they are aged enough and stunted in growth. Well fed ones will be at three to five pounds by the end of their second summer. Mine had eggs in them by then, but no fry were seen, even though I provided habitat. I suspect, in a pond, adult bluegill and small LMB will eat any CC fry fairly quickly.

I think to have a successful pond spawn, that the CC would have to be the only fish, except maybe fathead minnows could be in with them.

This pond has only res,cc and fhm

I have read that CCs need a cave-like structure for spawning and to protect the fry. Ideally, an old time large milk can where the neck, at say eight inches diameter, is smaller than the interior, at say sixteen inches diameter. I haven't found any reasonably priced old milk cans, so I'm looking at ceramic planters or cutting a hole in twenty gallon plastic food barrels. Add gravel and sand and sink. I don't know how deep to place.

I've had reproduction in my 3 acre pond and have at least two year class sizes. Originally stocked September 2013.

I did not specifically put spawning structure in for CC but have numerous things that could naturally be cavities including very large stumps turned up on the side, some concrete slab ledges and some old plastic containers of various kinds.

My LMB population has failed to recruit which I blame excessive reproduction of BG. So the modest LMB predation might explain why my CC spawns have been able to recruit new CC. I have six inch specimens and ones about a foot long as well as the original fish which are 3#+. I do not seem to have excessive reproduction. I just catch the smaller CC occasionally which is fine with me. A small amount of recruitment would be perfect.

That has been my experience to date.

I have placed pieces of pvc pipe with one end closed off with plywood. I will see if my 1 1/2 -2 pound ccs will use them to spawn. I placed them in 4-6 and 7feet. The pond only has res and thousands of fhm.plus the cc.

My backhoe tires are beyond worn out. When I get them changed, I will sink them as spawning structure in the pond that will have blue catfish. I already have 2 plastic 55 gallon drums in there.

My experience is similar to Snrub's. I did not put in any CC dedicated spawning "caves" but I've still seen a very small number of recruits. I suspect mine found a nest they like in my piles of broken concrete slab. I think an important factor is keeping the slow moving new spawn from being eaten so they will need lots of cover near your "caves." FWIW I've read that you want the opening of the nests facing away from shore in 6 to 10 feet of water.

they'll also use muskrat/beaver holes, rip rap, cinderblocks, etc to spawn in

We have not seen any signs of CC or BC recruitment in our 5 ac pond. There is 14” pipe 8’ long in several places. Unless LMB are gobbling them up. Got a good spawn of LMB seen in several places .... maybe 500 or so in each pod.