imn glad to hear that people are smart enough to ask questions and do research on the fish before blindly making purchases!!
whatever your decision make sure its educated. good luck
depending on species.
but the most common ones would be orinos/monos/ocells gettign to about 2 feet.
and temensis getting to 3 feet and growing much faster.
I keep a leiarius longibarbus with my cichla. They also grow to 2ft and grow at about the same speed as the cichla too. Not had any problems with them together at all and the cat loves to clean up.