Frankly, it's the general rule because it has been well-established based on the previous experience of many others. and no, i'm not mad because it didn't work...in fact, i've had it work with both silver and black arows with certain species of gars for semi-extended periods of time (almost a year in both cases, not the matter of months or weeks that many tend to post about).
that being said, this forum is about gars, not arows...through quite a bit of research we have found that gars are best kept on their own, sometimes not even with other species of gars. if they are kept with tankmates, there are some that work well (in most cases) such as bichirs, SA/AU lungfishes, African bonytongues, etc...arowanas are hit-or-miss, and it's often times a miss. the "silvery fish issue" can spook the gars, draw their attention to act aggressively, or damage both fishes. it's generally inadvisable. also, because of the differing growth rates (especially with the case of the OP here), they seldom match up until both fish are "done" growing or at least of 1.5'+
even though it has worked for me, i don't advise others to do it, it's not in the best interest of the gars in most cases. plenty of you all come on to the forum and talk about your one exception and preach it as a rule...or the post below that says it all has to be trial and error. some of fish keeping is trial and error, but there is a reason for previously established practices and forum information.
if you want to try the combo, just go ahead and do it...don't ask for advice if you already have the mindset that you're going to do it no matter what. again, here on the gar forum we give the information which is most beneficial to the gars. the attitude is a byproduct of having to deal with the same type of posters every time this (or similar topics) come up. perhaps i should go in the other direction and just consider it as the laughable excerpts of advice/accounts that they are--
--solomon
- it doesn't always have to be a trial, so that's not the best approach.
- it is good, however, (and as you state) to have an alternative. but in some cases it doesn't take much for one encounter to be fatal...such as gars breaking their backs. this is why we try to give the best advice for keeping the gar healthy...so others don't have to do all the trial and error that has been previously done--
--solomon
