Stocking Question

[Aquatic_Adam]

I have a 40 long aquarium. Currently it is lightly planted with 3 large pieces of driftwood. The current inhabitants are 3 bichirs. A delhezi, a senegal, and a tuegelsi. It has worked so far because they are all fairly young. I'd say the oldest it's probably at tops a year old. I was in my favorite LFS and I found an unlabeled bichir. It was a polypterus mokelembembe. For those who don't know, they are rare. It was being sold at $45. I really wanna get it because I fear that I will never have this opportunity again. But I also want to be a responsible owner and not overstock my aquarium (which it is if I keep all the bichirs I have now in there). I a currently a student to be graduating college in a year. After I graduate o was gonna upgrade tanks.

But the question remains. Do i get this rare fish?