fish tank water

Question
What sort of stuff are in fish tank water? I'm doing a science project on it, I want to know things like the fish's waste and the other things found floating around there. I would be really really thankful if you could answer or send me a reply. Please and thank-you!

Answer
What is in fish water.... Hmmm... that's a big one :)
There are all types of things in the water. There is helpful bacteria that helps the fish stay healthy and his scales free from harm. There are these little worms called Planateria that eat the wasted food from the gravel.
I'll dig up some more information so that I can provide you with the actual names of the bacteria and some of the other things in the tank. It's 7:AM here now, I should get back to you by 1-2:00 today :)