Okay, weird, it's in the same listing as one thing, with a photo of the cube looking one. 12 is what I was hoping for to fit where my current is. I'm tired of the rounded front being impossible to scrape & not being able to get a lid for it to help with evap. Going to be a slight increase in size but should be fine. Thank you.The 14.17 is the the 3.8g (has the side filter so more peninsula style) tank the 12.21 is the one I have and it the 4.1 gallon (cube style).
Can't wait to see how yours turns out once it's stocked!