How often should I change betta fish water, and what factors must I consider in determining the frequency of these changes? Is it merely a question of aesthetic cleanliness, or does the well-being of my betta hinge on a more nuanced understanding of water quality? For instance, could the size of my aquarium, the presence of a filtration system, and the density of my fish population significantly influence the answer? Should I take into account the weekly fluctuations in ammonia and nitrate levels that could tip the balance between a thriving aquatic environment and a hazardous one? Furthermore, how do variables such as overfeeding or the introduction of new plants or decorations impact the rate at which water quality deteriorates? Ultimately, is there a universal guideline or a set of best practices that can inform my approach, or does it necessitate a more individualized strategy based on continuous observation and analysis? What insights can experienced aquarists share regarding their methodologies?