Several months ago I upgraded to a nice, new, shiny stainless steel racking cane (this is the thing that gets stuck in carboy while siphoning beer from one container to another). I had a plastic racking cane that was not being used. I decided it needed a use.
There are many uses, but I decided to use it to help clean my fish tank. You may recall we replaced a dead fish with some new fish around here. We did this primarily because dead fish are really boring and eventually smelly.
I try to clean the tank regularly. It is a pain, so I came up with a brilliant solution using my old racking cane.
Here's how it works: I put the racking cane in the fish tank and run the tube out of my deck door. I start the siphon and send the used tank water out to the grass under the deck. The fish stay in the tank. As the water gets lower I add more water to "wash" the rocks and stir up any settled fish poop. Water out, water in. I exchange a few gallons of water to ensure the tank is clean (or almost clean). Finally, I let the tank water get to about 3 inches deep. I cease the siphon and fill the tank with fresh clean (treated) water.
Here are some really crappy pictures to demonstrate my method.
I know, the pictures are lousy, but I think you get the point.
 We had 4 but are down to 3.
 Hehehehehe, yeah, whatever.