i used to have one of these guys who as 14" long. He was the laziest fish ever. he always stayed in one spot, and only ate if the food got close enough to his mouth for minimal movement. I'd sometimes see snails crawling on him. tankmates included an oscar, a jack dempsey, a redtail catfish, and a bichir.
I eventually had to get rid of him (along with all my other fish) when my landlord had me get rid of my monster tank. Brought him to a petstore in wichita, KS where he lived out his days till the store closed down. Even at the petstore, he had the same, unmoving attitude. was always in the same exact spot every time i visited the petstore. Dunno what happened to him after the store closed down.