how big is your QT? I don't know if you should but I would think if your QT is big enough for one then why not... but wouldn't an over the back be suffecient enough
I have a sponge filter power head in mine and it's a 10 gal .... I don't know if thats a bad idea or not though... but I didn't know what to put in it, and I had that so I threw that in there but I haven't put any fish in it yet either I just set it up because I read that its was a good Idea