How to tell difference - Blue vs Channel catfish

Blue catfish (2 lb) from trotline - One Channel (1.75 lb) - rod n reel / magic bait - other channel cats (5 keepers) on yoyo at night / magic bait - from my fishing pier i.e. shallow water at night. I threw back over 1/2 dozen channel cats from yoyo's - I was checking them every couple hours and got bunch of really small (less than a pound) that kept stealing bait - otherwise I would have had a LOT of fish to clean instead of just 7 that were 1.25 to 1.75 lb

Magic bait has moved to top of my list for best catfish bait in the world but Secret 7 is not far behind. In fact, I often mix the two as shown in earlier video i.e. I flatten out the magic bait and then use stick to put on / in some Secret 7 - then wrap it around a treble hook so the Secret 7 is 'squirting out the top' and the Magic bait holds the mixture on the hook (there I gave away my Secret about Magic bait and Secret 7 catfish bait

P.S. I only use Chicken Liver and Chicken Blood flavor :)