Wow...what an amazing thread! I got through the first few pages and then stopped to make sure that I hadn't accidentally logged in to Fishlore by mistake...

Okay, here's how it works: You take all your fish and dump them into a clean plastic pail...no water, just fish. For obvious reasons, you must move quickly. Now weigh the bucket'o'fish, and then replace the fish into their tanks. Try to put them back into the same tanks you took them out of. Weigh the now-empty bucket and subtract to get the actual total fish weight.

Now, take that weight (in pounds...sorry, Australia!) and convert it into inches, using the formula P(2#) x (T-

Pi) + 3 x F/A , where P = pounds of live fish, T = temperature in degrees Kelvin, F = the magical Fish Constant, which can be found on the internet and varies from species to species, and A= altitude above sea level. Now take the result (which will be expressed in square feet), and divide by 144 to convert to square inches. (I won't even get into the whole square inches versus inches squared thing...).

Take the resulting number and multiply it by the length of your aquarium in inches, then divide that answer by the width of your aquarium in feet. Now measure the height of the tank in furlongs, take the square root of that and add it to the total you just calculated. If you live in the southern hemisphere, you will need to add a negative sign to this result.

Now, the important part: measure the pH of your source water, and take the inverse square root of that number. Multiply it by the previously calculated total, and then add 4, just for fun. It is often suggested that barometric pressure needs to be factored in, but that would just be silly.

Now, calculate the average speed at which your fish typically swim. I won't go into detail on how this is done, as it should be intuitively obvious. Take this velocity, convert it to rods-per-nanosecond, and then double it. Now square the answer, and then take the cube root. Multiply your previously calculated total by this number and then just convert it to a base 8 number. This will be the number of cubic parsecs of water the fish in your bucket will require for health and happiness.

It should go without saying that this calculation needs to be done at least weekly, to keep up with the growth of the fish. Re-calculation is also advised after each fish death or addition of new stock.

See? It's not nearly as complicated as some of you seem to want to make it...