Lol, I love redtail catfish and I'm glad yours looks magnificent and happy and well cared for! They really are awesome fish. IMO it's still a travesty that they're sold considering just how few people can house them properly.
Funny story about RTC's; I was watching river monsters with my fiance and her family and Jeremy Wade hooked into a really big fish. Between my fisherman's and fishkeeping knowledge I was fairly certain very quickly that he was hooked into a RTC and called that that's what it was going to be. Sure enough, he pulls up a 3.5' redtail.
I bask a little bit in my fish expertry, and then inform them, "Y'know, you could buy those at the Petsmart in Bangor!"
My (almost) mother-in-law looks at me, mouth agape; "You can BUY those!? As PETS!?"
"Yep."
She asked me a few more questions about keeping them and I took the opportunity to explain that not every fish you can buy is good for fish tanks. It was a good teaching moment!