h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Sounds like a good plan. Unfortunately, for someone like me who keeps their mega-sized-monster-goldfish in a large tank (rather then a bowl), this dosn't work, since the tank is WAY to heavy to bring to the sink. So, for anyone elso who shares this problem, my solution is to siphon the water out my window. It takes a long time, but it works really well. It's something, I'd suggest, that you start, go do something else, and then finish a while later.

Yes but hey don't forget about it! There's nothing worse than seeing your friendly fish flapping their last on a bed of damp gravel.

It's best to empty no more than a third of the water out of the tank in any one go - it gives the fish less of a culture shock than changing all the water at once - especially if you have tropical fish which like to keep warm at a steady 82 degrees or so. That's F not C.

I siphon the water into a bucket, then move the siphon into a second bucket whilst I rush to empty the first. Then I return to find that the siphon has slipped out and is pouring water & fish poo over the lounge carpet.

I find that this is the best way of ensuring that my wife doesn't ask me to clean the fish tank.

We also have(or rather my daughter has) the larger version: it gets a good scrub down inside every month to get rid of algae, and "we" (ie usually me) change the water etc more like every 3 months or so.
Poor fish I hear you say.
BUT - the tank has a super-duper filter system attached to an air pump, which keeps the water remarkably clean and unsmelly.
The fish haven't complained yet, and the eldest is now approaching it's 5th birthday without a sign of disease, and is almost 6inches long. (Hence the infrequency of emptying the tank - you almost need a fishing rod to haul it out!)

I have noticed that the state of the water does depend on the type of food used: fish flakes make the most mess, ant eggs hatch if you are unlucky, but we've settled for little pellets, which seem to be the best.

With my hectic lifestyle I could never find the time to drag the tank to the sink etc. etc. so everynow and then, the tank gets a quick 'hoover' - I've attached an old and rather soft toothbrush to the end of a syphon hose and vacuum around the walls and floor when it begins to look rank. Then just top up the water I've sucked out.

And the fish are still alive

Why put clean water in anyway? They haven't drunk the stuff I gave them last week!

I just got a fish, and so to add a bit if uniqueness to the bowl I took a permanant marker and wrote "So Long, and Thanks for All the Fish" on the side! Its started a few conversations, though most have ended with me looking slightly nuts