My old Oscar in the dealer tank, before I got him (took the picture so I could research it, I thought it had odd fins). He died at 13'', just shy of 13.5''.
Heres my 12in. midas got him from Pet Smart at 2in.. He lives in my 84gal. I feed him Hikari Gold & Bio Gold at his base diet, also lettuce, cucumbers, and frozen or freeze dried krill. My Peacock CICHLID doesn't eat the vegetables. I got him/her? at 3in., now its about 12in. I had to teach it to eat pellets. I did it by showing it frozen krill above the water, standing back from the tank, and throwing them into the water. Basically playing fetch! The next pics. are of my uncles Cherry Red Flower Horn, he bought him for $200 at 3in. In the pics. hes about 8in. He lives in a 115gal. And the last pic. is of a 12in. Snake Skin Flower Horn that I sold to my brother about a month ago.