Does the amount of organisms in the water determine wether the water quality is good or not?

The amount of organisms in water can indicate its quality, but it's not the sole determinant. High diversity and abundance of aquatic organisms often suggest good water quality, as they indicate a healthy ecosystem. However, excessive numbers of certain organisms, like algae, can signal pollution or nutrient overload. Thus, water quality assessment requires a combination of organism abundance, diversity, and other chemical and physical parameters.