[bigger_cheese]

Are the fish always the same color/is their color distinct from the background.

I work at an industrial plant we have been able to measure a lot of things simply by analyzing the pixels in the video. For example one application we have a camera pointed down at a conveyor belt. The conveyor belt is one color and objects on the belt are a distinct different color.

- we just count how many pixels in a given frame are a specific color/brightness. Then you can easily work out how much of the conveyor belt has material on it in any given frame.

So if you are tying to work out what section of a video has fish in it you could count how many pixels are a different color to the normal background color.