I personally have 2 limas, the first one I got 7 months ago, and the other 4 months ago. The first one grew from 2 inches to 9 inches in 7 months and the second grew from 2 inches to 11 inches in 4 months. So it really varies. the oldest one I have is a picky eater and the other happily gobbles up anything meaty put into the tank. I have done a lot of research on this fish and the largest recorded individual that I have found was 33 inches. that is record size though in the wild. Largest in aqaurium that I have seen is 21 inches, but with enough room and proper care I am sure anyone could grow a world record. Many fish can be kept at much larger sizes than their brothers and sisters in the wild with enough care and attention to diet and habitat. One member here grew a planiceps catfish larger than the current world record. So yeah many sites list the max size of limas at 14-20 inches, just remember where they come from and that their brothers and sisters there average much larger and they do have that potential! Many times the averages given are for reported aquarium raised individuals. Mortality in aquariums is much higher due to improper care and diet. I am sure we will see an increase in the health and size of our fishes with the knowledge and expirience shared on forums like this one! Good luck and keep us updated!