Alot of factors go into growth of a fish lol. Thanks for sharing green that thing is a monster. I think you can get an aimara to a size over the span of years of course with live food, current, a large tank or pond, and keep it solo. Some of the main points is keeping the fish happy so it has an appetite, keep it so that it has to work for the food such as in the wild, and provide the space needed. And of course time and dedication cause these fish are likely 10+ years old.