Just a warning they can be very hard to train offa live. in this reguard the sticky for converting true gar should also apply to these guys.. floating foods like crickets and krill are a good start and it should take to pellets fairly readily from there... they are also fairly smart and will learn to eat other food from tank-mates. Just make sure he doesn't starve.
That is not actually true for the pike characins, Boulengerella maculata has spots its entire life, Boulengerella lateristriga is another commonly available species also labeled as "marbled gar" that has a stripe running laterally down its body. Boulengerella cuvieri is also seldom available and look much like B. lateristriga, but they have a different color caudal fin and they grow much larger.
That's precisely what they are. I have also seen these labeled as South American gar. The specimen you most likely saw was Boulengerella cuvieri which has more red than B. maculata and B. lateristriga, although, I have seen some "pink" looking B. maculata and some reddish looking B. lateristriga.