I am an elementary science lab teacher and have been given an aquarium. I want to set up a natural pond that the students can observe throughout the school year...but I don't even know where to start. Can you give me some pointers? I also live around lots of natural rivers and have the means to introduce natural plants and critters to the pond. Thank you!!!

I'm not sure where to start either! There's so much to learn and to teach. Most of what I would say is somewhere on my web site. You can buy something like a Rubbermaid stock tank, plastic storage container, or just an aquarium with no lid to set up an indoor pond. You can then stock it with native plants and animals from your area. Here are some pages on my site that I suggest reading:

Indoor ponds - http://www.fishpondinfo.com/indoor.htm
Wildlife ponds - http://www.fishpondinfo.com/wildpond.htm
Tub ponds - http://www.fishpondinfo.com/tubpond.htm
Water chemistry - http://www.fishpondinfo.com/chem.htm
Native fish - http://www.fishpondinfo.com/misc2.htm
Microorganisms - http://www.fishpondinfo.com/micro.htm
And more!

Thanks for the links. I guess the questions that I have are can I just bring in water from the river and add an oxygen source and then introduce new animals and plants? And also do I need to put gravel down or just sand? I really appreciate this, I know my kids will love it!! Thanks!!

A river ecosystem is a little different than a pond ecosystem. River water is high in oxygen and constantly replenished so it's generally cleaner. Different animals live in rivers versus ponds. There are usually more microscopic plants and animals in the more stagnant pond water. If the river water is clean, it can probably be used to start an indoor pond. You may want to test the pH, hardness, nitrate, etc. of the water you're both putting into the tank and from where you might get any animals. If the water chemistry is a lot different, it's hard on the animals. Some ecosystems have gravel bottoms and some have sand bottoms. Some animals need sand but most do fine with gravel. Gravel is a lot easier to deal with and to keep clean.