No, hes definetly no irridescent shark. I'd say start up your fryer. "Tonight, we eat as kings..."lol. What size is he now? I read on one page that in properly maintained adequate aquaria, a channel cat can reach 51 inches in length...

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Nope, definetly not a trustworthy LFS. You might see if you can get a refund on that puppy. What did they try to call him? What did you pay for him?
Whats really funny is that you could probably have gone down to your local pond and caught a healthier, F0 one for free...
Good luck with this one.