Onion Plant Question

So, I have had this plant for quiet some time now, However for the past year, I have had no new growth. I have literally had the same 4 leaves at the same height for the last year. After adding a pressurized co2 system, I have noticed new growth, however I am uncertain on what to do. It looks like I am getting two new plants growing from the bulb itself, is this normal? Normally i though new leaves should grow from the middle, and not from the side? Attached is a pic, any thoughts would be nice. Thanks

That is just the way it reproduces.