Hmm, it is still a great deal, but it is also a good trick. The tanks are probably bought cheap in the first place so they still make a little money on them even at that low of a price. Then you get people like me who say, oh, my 10g is a little small, and I could use a hospital/qt tank. I think I will upgrade to a 20g. I was planing to do so, but then I sat and thought a minuite. You still need a light (my 10g light would probably do the job still), you need an upgraded heater if yours isnt already overkill. You need a new lid that may cost more than the tank itself. You need a new filter if you didnt buy one much bigger than needed. (hey, at least I thought ahead there
). You will prob need more gravel/sand/whatever. And you may need a sturdier stand. So really, sales probably go up on all of those items as well, increasing their total profit.