As FLBettaCouple said, they surface feed and grow 12"
I have a needle nose gar myself. They can be quite peaceful if kept with fish large enough to not be eaten. I keep mine with a black ghost knifefish, an electric blue jack dempsey, a red tailed shark, and a senegal bichir and there's never been a problem between them. However needle noses are quite finicky eaters that will only eat small fish the size of a guppy, so if you get one then expect to be buying feeders every so often. And yes, you may keep them around 2 of them in your 75 gallon, but I would say no more than 3 to prevent over filling the surface because they are active swimmers that need space to dart.
I hope that answers your question... If you have any more questions about them, please feel free to send me a private message.
