Yeah thats the plan just because the Gars are so skinny when young. The LFS can get them at that price year round (he knows the guy who owns the farm)... I just happen to like the pattern on the Tropicals a little more when they get bigger. I'll see what I can get for the Peacock bass... I'll probably get more though... I love the peacock bass/Gar combo and its worked for me before w/ florida gars. As for the Knife.... I really just dont him too much... really agressive... too agressive to put up with when you have such an expensive gar. Which one in your experience is more touchy health-wise though? Tropical or Cuban Gar?
To put it bluntly, it's pretty stupid to get more peacock bass in order to try that combination in hopes that it will work again considering that you've been saving up & waiting to get this gar. I know that I'd be pretty mad if I just got an awesome & expensive gar that then gets injured/killed by a dumb peacock bass. I'd say that the knifefish should go as well if aggression is an issue.
Of those two gars, I've only ever had a Cuban gar, and I never had any issues with it health-wise. If something was off, then its color would change; as soon as I fixed the issue, then it would change back to its normal coloration. If you can keep your water conditions stable & clean, then you shouldn't have any issues.
I never was able to obtain a tropical gar as all of the ones offered for sale then & now are pretty overpriced considering that I know how much the farm charges for them. Besides, the tropical gars don't have to pass through Canada first to get here; having to add extra steps to make them legal in the case of the Cuban gars is one reason why they're normally fairly expensive.