*In home aquarium Exodon grow up around 4~5 inches, most likely 4 inches and rarely see them bigger than 4.5 inches (most died before they can reach that size)

*You would need a large school of Exodon to keep the salvation low between them and they will need to feed more than 3 times a day, because of the high bio load you will need a very very strong good filtration system and more water change to keep water quality in check.
*Exodon is not a cheap fish no matter you buy in nearby LFS or order online the lowest cost will be $7 each (other option is that you have good relationship with your LFS and ask them to order for you then the cost would be around 3~3.5 dollars each per 100).
*You will need a shoal of 25+ the more the better because they will kill the weakest one in first few weeks. When everything settled in (before you giving up on them)

they still fight/salvage each other here and there but nothing cause major damage to kill them.
*They do good in Biotope/heavy planted tank for hiding space and escape of bully one sight.