Canister Filters above water level?

I've seen lots of pictures of tanks with canister filters mounted above the water level, or even ponds with Fluval FX5 canisters standing next to them.


How the hell does that work?

 

Hey Sauron - exactly the opposite of having them on the floor - pump into it and gravity feed out - the pro is that there can NEVER be a flood mishap - well never say never

 

So you just reverse the motor in the thing?

Even so, the setups I've seen it doesn't seem feasible that it would siphon out either, with the top of the canister being equal if not lower than the lip of the tank.

Just found it interesting, and wondered why people bothered with the trouble and not just hide it in a cupboard underneath.