Those guys are known as the 'gentle giant' they don't have teeth and typically feed on algae. Amazing right? as a fry, they are about 1/4 inch long, by eleven days they are 1 inch long. So they grow pretty fast.
That's the website about different catfish. I was researching my paroon and found disheartening things but that also has some other catfish (ones that can get 16 feet long) Like "Silurus glanis, the wels, have been reported up to 16 feet 8 inches and weighing over 730 pounds"
Ever want to go swimming in Romania...