This is just from personal experience, but I have a lot of it, and would like to pass this on. Many members ask the question about fresh vs. frozen baitfish, and are concerned that they are missing out if they use frozen bait. I have caught 688 blue catfish on rod and reel in the past 7 months, up to 84 lbs, the vast majority of them on frozen baitfish. I even have a freezer in the garage dedicated to frozen bait. I freeze skipjack herring, threadfin and gizzard shad, redhorse suckers, and of course bluegills. I freeze these fish whole, with the exception that I will trim the tails off of the larger fish so that they will fit in the freezer bag. I personally like to use a vacuum sealer to bag the fish because the bags are stronger and fins won't puncture them, but this is not a requirement - a good zip-lock type of freezer bag will work fine. I try to bag enough fish per bag to last 1/2 to 1 day of fishing. I keep the bait frozen in a cooler and saw off only what I need each time I re-bait. A serrated knife or a game shears works best for this. I usually use "steaks" cut across the fish, about 1" to 1-1/2" wide. I bait the hook and use these "popsicles" immediately, letting them thaw in the water where they release the blood and oils. The blue cats don't seem to be bothered by the cold bait and will often hit it immediately. The unused part goes back into the cooler so that it doesn't thaw and dry out. Use fresh bait? Absolutely! Is it better than frozen bait? Probably, but the difference that I have found is so small that I have no reason to spend a great deal of time trying to get fresh bait each time I want to fish. I make specific trips to catch bait whenever I feel like it, and normally just take the frozen bait when I go for the blue cats. I hope that this eases your mind about using frozen bait for blue catfish. I cannot say how this works for other species of cats because I have limited experience with them, but it sure works on those big blues! Good Fishing!