Dopey and Mopey.....

[sterling_mcdaniel]

I would expect 2.5 to 3 feet long but they do have the capability of 4 feet. oh and they will lose those spots as they get bigger.

 

[I<3fish]

Channel cats rarely grow over thirty inches. I say don't expect more than this.

 

[blurock]

They get large, and do it very quickly. They lose their spots as they mature, and the silver ones are usually labeled as "blue channel cats" in the trade, though there is a debate on weather they are true channels or a hybrid of blue cat and a channel cat, and will sometimes darken with age.
Mine started off that color, and here it is now

 

[flyin lizard]

Update for you,, the rtc x tsn is doing great and boy does he love earthworms..putting on some size too..

 

[Cichla dude]

4'+

not that big

 

[perfect_prefect]

in the wild they can get 4'+ so they can get that big, do they under normal aquaria situations no. most people couldnt house a 4' fish so they stunt and stay at about 3' but if you have the right set up it could get 4'.