Fred the fish is a great water pollution activity that shows what happens to fish in polluted rivers and streams. I've used this lesson several times (even with adults)and it's been a success.
Fred is a light-colored, fish-shaped sponge which hangs from a weighted string into a large jar or punch bowl, about 3/4 full of water.
A scenerio is read by different students (9). Each step tells of Freds travels down stream, starting with a clean river and gradually adding more and more pollution. Different containers of "pollution" are added by the students along the way. For example, when Fred swims under a highway bridge, some cars traveling across the bridge need to be repaired because they are leaking oil onto the road. The rain is washing the oil into the river below. The "pollution" added to the jar at this time is actually maple syrup to represent the oil.
In addition - students can practice using adjectives by making a list of how Fred looks after each addition.
If your interested in the script and all the "pollution" items, feel free to email me!