I like to think of the streets as a big fish tank. I guess that is because I grew up in a house that kept a lot of tropical fish.    In a really good and interesting community tank there are lots and lots of different wacky things going on in all directions and at all levels. These are always the most interesting tanks to look at.    I learned that the things going on at the bottom levels are as (or more) important than the things floating around up above. If the bottom gets out of balance, the rest of the tank starts to stink.    There are two ways you can keep the bottom of your tank together. You can take the labor intensive, control oriented, antiseptic approach which forces you to constantly clean and churn up your tank scene. Or, you can choose to introduce and encourage inhabitants who create a healthy environment for you.    These are often the most interesting members of the whole fish tank.    On the streets there are hundreds of different levels going on all at once in a very complex environment. As hard as a city may try, it can never create an interesting yet antiseptic environment in a public space. This is where healthy street level activities, like Street Performance, help tremendously.    Healthy street level activities create a presence which fills up the street space and discourages unhealthy street activities. It is not in the Street Performer´s interest to allow disruptive influences within his/her area of performance. This helps to police the area and create a web of responsibility.