Why does size matter in a koi fish tattoo?

The biggest thing with size, and this goes for any tattoo, is the amount of detail. Every day, we have several people bring in designs and want us to do it as small as possible. You have to remember that the skin is a living organism, and will move, expand, contrast, and change consistancy throughout the year(s). If you try to go too small, you will have a black spotch or something that just doesn't make any sence. Readablilty is very important with a tattoo. If nothing else, look at a different view point. Think of the last really great tattoo you saw. Now that you have that image in your mind... how big was it?