They can get 3' or a little bit longer. They are a pimelodid catfish called a marble catfish or marble pim, the scientific name is the one I listed above. They are mostly nocturnal, and will eat pretty much anything that will fit in their mouths. I would caution against putting him on the floor for pics. I could have Made a postive ID from a top shot. I keep all my large catfish in tubs and take pics from above. Good luck with him. I'd feed shrimp and pelletes if he'll take them. They are fairly common, and I would say that they are not worth much more at that size then they are at a smaller size due to the fact that not many people will want a fish that size. I paid 45" for an 8" one. Probably wouldn't pay more than $75-$100 for a 16".