hey guys, sorry for the delay on getting to this question (and i'm sure many others) i know richard has also been extremely busy as of late, and it doesn't look like things are going to let up much in the future...when it rains it pours.
anyway, there is no great way for telling if a gar is truly stunted (by our captive definitions) or not if you don't have a relatively accurate age on the fish. in captivity, it is inevitable that gars are going to stunt to some extent. we are not talking about aquaculture facilities with large ponds or anything like that, we are talking about the relatively typical home aquaria.
a gar is most vulnerable to stunting in its first year of life, if it isn't given the proper diet, water quality, and space, it can stunt and this can cause problems down the line (or just kill the gar early on). beyond that point, if the gar has made it, it will likely survive...which seems to be the case with the gator gar in question. if it has been that size for 2-3 years now, it is unlikely that it will grow by any leaps and bounds (if at all)...maybe fractions of inches per year.
one should always give gars the appropriate amount of space in responsibly fish-keeping, so at least a 2' wide tank would be a step up for the gar in its current home, but wider is definitely better.
hopefully that touched on some of your questions and provided some response, please feel free to post with further questions or comments or further clarification. also, RE: one of the above posts...gator gars definitely do NOT grow only 0.5" per year after their first year (in the wild/if they reached 24" in the first year). if they are, they are definitely being stunted, but holding a yearling gator to just that amount of growth (IF it grew to 24" in the first year) would be tough in and of itself.--
--solomon